feat: add ParseSchema to SDK

[cbaker6]

New Pull Request Checklist

• I am not disclosing a vulnerability.
• I am creating this PR in reference to an issue.

Issue Description

Schema and Class Level Permissions are current not implemented in the SDK, preventing the developers for creating/updating/deleting Parse schemas directly in Swift.

Related issue: #n/a

Approach

Add ParseSchema, ParseCLP, ParseFieldOptions types to the SDK. Since ParseSchema requires the use of the masterKey, this should only be used when using the Swift SDK on a server.

Example usage can be found in the Playgrounds:

Parse-Swift/ParseSwift.playground/Pages/20 - Schema.xcplaygroundpage/Contents.swift

Lines 96 to 252 in c32e269

	//: First lets create a new CLP for the new schema.
	let clp = ParseCLP(requiresAuthentication: true, publicAccess: false)
	.setAccessPublic(true, on: .get)
	.setAccessPublic(true, on: .find)
	//: Next we use the CLP to create the new schema and add fields to it.
	var gameScoreSchema = ParseSchema<GameScore2>(classLevelPermissions: clp)
	.addField("points",
	type: .number,
	options: ParseFieldOptions<Int>(required: false, defauleValue: nil))
	.addField("level",
	type: .number,
	options: ParseFieldOptions<Int>(required: false, defauleValue: nil))
	.addField("data",
	type: .bytes,
	options: ParseFieldOptions<String>(required: false, defauleValue: nil))
	do {
	gameScoreSchema = try gameScoreSchema
	.addField("owner",
	type: .pointer,
	options: ParseFieldOptions<User>(required: false, defauleValue: nil))
	.addField("rivals",
	type: .array,
	options: ParseFieldOptions<[User]>(required: false, defauleValue: nil))
	} catch {
	print("Can't add field: \(gameScoreSchema)")
	}
	//: Now lets create the schema on the server.
	gameScoreSchema.create { result in
	switch result {
	case .success(let savedSchema):
	print("Check GameScore2 in Dashboard. \nThe created schema: \(savedSchema)")
	case .failure(let error):
	print("Couldn't save schema: \(error)")
	}
	}
	//: We can update the CLP to only allow access to users specified in the "owner" field.
	let clp2 = clp.setPointerFields(Set(["owner"]), on: .get)
	gameScoreSchema.classLevelPermissions = clp2
	//: In addition, we can add an index.
	gameScoreSchema = gameScoreSchema.addIndex("myIndex", field: "level", index: 1)
	//: Next, we need to update the schema on the server with the changes.
	gameScoreSchema.update { result in
	switch result {
	case .success(let updatedSchema):
	print("Check GameScore2 in Dashboard. \nThe updated schema: \(updatedSchema)")
	/*:
	Updated the current gameScoreSchema with the newest.
	*/
	gameScoreSchema = updatedSchema
	case .failure(let error):
	print("Couldn't update schema: \(error)")
	}
	}
	//: Indexes can also be deleted.
	gameScoreSchema = gameScoreSchema.deleteIndex("myIndex")
	//: Next, we need to update the schema on the server with the changes.
	gameScoreSchema.update { result in
	switch result {
	case .success(let updatedSchema):
	print("Check GameScore2 in Dashboard. \nThe updated schema: \(updatedSchema)")
	/*:
	Updated the current gameScoreSchema with the newest.
	*/
	gameScoreSchema = updatedSchema
	case .failure(let error):
	print("Couldn't update schema: \(error)")
	}
	}
	/*:
	Fields can also be deleted on a schema. Lets remove
	the **data** field since it's not going being used.
	*/
	gameScoreSchema = gameScoreSchema.deleteField("data")
	//: Next, we need to update the schema on the server with the changes.
	gameScoreSchema.update { result in
	switch result {
	case .success(let updatedSchema):
	print("Check GameScore2 in Dashboard. \nThe updated schema: \(updatedSchema)")
	/*:
	Updated the current gameScoreSchema with the newest.
	*/
	gameScoreSchema = updatedSchema
	case .failure(let error):
	print("Couldn't update schema: \(error)")
	}
	}
	/*:
	Sets of fields can also be protected from access. Lets protect
	some fields from access.
	*/
	var clp3 = gameScoreSchema.classLevelPermissions
	clp3 = clp3?
	.setProtectedFieldsPublic(["owner"])
	.setProtectedFields(["level"], userField: "rivals")
	gameScoreSchema.classLevelPermissions = clp3
	//: Next, we need to update the schema on the server with the changes.
	gameScoreSchema.update { result in
	switch result {
	case .success(let updatedSchema):
	print("Check GameScore2 in Dashboard. \nThe updated schema: \(updatedSchema)")
	/*:
	Updated the current gameScoreSchema with the newest.
	*/
	gameScoreSchema = updatedSchema
	case .failure(let error):
	print("Couldn't update schema: \(error)")
	}
	}
	//: Now lets save a new object to the new schema.
	var gameScore = GameScore2()
	gameScore.points = 120
	gameScore.owner = User.current
	gameScore.save { result in
	switch result {
	case .success(let savedGameScore):
	print("The saved GameScore is: \(savedGameScore)")
	case .failure(let error):
	print("Couldn't save schema: \(error)")
	}
	}
	//: You can delete all objects your schema by purging them.
	gameScoreSchema.purge { result in
	switch result {
	case .success:
	print("All objects have been purged from this schema.")
	case .failure(let error):
	print("Couldn't purge schema: \(error)")
	}
	}
	/*:
	As long as there's no data in your `ParseSchema` you can
	delete the schema.
	*/
	gameScoreSchema.delete { result in
	switch result {
	case .success:
	print("The schema has been deleted.")
	case .failure(let error):
	print("Couldn't delete the schema: \(error)")
	}
	}

TODOs before merging

• Add tests
• Add entry to changelog
• Add changes to documentation (guides, repository pages, in-code descriptions)

[parse-github-assistant]

Thanks for opening this pull request!

• 🎉 We are excited about your hands-on contribution!

[codecov]

Codecov Report

Merging #370 (ae88e8e) into main (56ec801) will increase coverage by 0.58%.
The diff coverage is 97.65%.

@@            Coverage Diff             @@
##             main     #370      +/-   ##
==========================================
+ Coverage   87.92%   88.51%   +0.58%     
==========================================
  Files         114      125      +11     
  Lines       12214    12970     +756     
==========================================
+ Hits        10739    11480     +741     
- Misses       1475     1490      +15     

Impacted Files	Coverage Δ
...thentication/3rd Party/ParseApple/ParseApple.swift	86.25% <ø> (ø)
...cation/3rd Party/ParseFacebook/ParseFacebook.swift	100.00% <ø> (ø)
...entication/3rd Party/ParseGithub/ParseGitHub.swift	100.00% <ø> (ø)
...entication/3rd Party/ParseGoogle/ParseGoogle.swift	100.00% <ø> (ø)
...Authentication/3rd Party/ParseLDAP/ParseLDAP.swift	100.00% <ø> (ø)
...cation/3rd Party/ParseLinkedIn/ParseLinkedIn.swift	100.00% <ø> (ø)
...tication/3rd Party/ParseTwitter/ParseTwitter.swift	100.00% <ø> (ø)
...Authentication/Protocols/ParseAuthentication.swift	77.04% <ø> (ø)
Sources/ParseSwift/Coding/ParseEncoder.swift	77.77% <ø> (ø)
...es/ParseSwift/LiveQuery/ParseLiveQuery+async.swift	81.81% <ø> (ø)
... and 45 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 56ec801...ae88e8e. Read the comment docs.