Expand the size analysis cli to support bundle size analysis

[Feiyang1]

Added a bundle command to the size analysis tool. It takes an array of bundle definitions (basically imports from packages) and analyze their size using either rollup, webpack or both.

As opposed to analyzing the size of each individual exports from a module, this command is useful for analyzing the size of a combination of exports from different modules.

Sample bundle definition file:

[
    {
        "name": "test",
        "dependencies": [
            {
                "packageName": "@firebase/app",
                "versionOrTag": "exp",
                "imports": [
                    "initializeApp"
                ]
            },
            {
                "packageName": "@firebase/firestore",
                "versionOrTag": "exp",
                "imports": [
                    "getFirestore",
                    "doc",
                    "getDoc"
                ]
            }
        ]
    }
] 

Run command on this file:
yarn sa bundle -i repo-scripts/size-analysis/bundle-definition-examples/bundle-definition-1.json -o res -b both

output:

[
  {
    "name": "test",
    "results": [
      {
        "bundler": "rollup",
        "size": 148098,
        "gzipSize": 48871
      },
      {
        "bundler": "webpack",
        "size": 192989,
        "gzipSize": 62322
      }
    ]
  }
]

[changeset-bot]

⚠️ No Changeset found

Latest commit: 212b0f5

Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. If these changes should result in a version bump, you need to add a changeset.

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[google-oss-bot]

Binary Size Report

Affected SDKs

• @firebase/util

  Type	Base (49378bf)	Head (3d9d8f9)	Diff
  browser	21.0 kB	21.2 kB	+279 B (+1.3%)
  esm2017	18.6 kB	18.9 kB	+269 B (+1.4%)
  main	21.0 kB	21.3 kB	+279 B (+1.3%)
  module	19.9 kB	20.1 kB	+263 B (+1.3%)

Test Logs

• Base (49378bf5): https://github.com/firebase/firebase-js-sdk/actions/runs/315943237
• Head (3d9d8f90): https://github.com/firebase/firebase-js-sdk/actions/runs/316008478

[google-oss-bot]

Size Analysis Report

Affected Products

No changes between base commit (49378bf) and head commit (3d9d8f9).

Test Logs

• Base (49378bf5): https://github.com/firebase/firebase-js-sdk/actions/runs/315943237
• Head (3d9d8f90): https://github.com/firebase/firebase-js-sdk/actions/runs/316008478