[CXX-2546] Create Encrypted Collection

[vector-of-bool]

Refer: CXX-2546

This changeset introduces the create encrypted collection convenience API, as outlined in DRIVERS-2312. This is used to create data encryption keys on-the-fly when creating a new encrypted collection. The C++ API is mostly just a wrapper around the underlying C API, with a few convenience overloads for optional parameters.

The error-initiating code may be questionable. It has been a while since I've worked in the C++ codebase.

[vector-of-bool]

Seeing failures on some replica_set configurations. Very mysterious $\ldots$

[kkloberdanz]

LGTM

[kevinAlbs]

LGTM with consideration to remove an overload and suggested simplifications.

[kevinAlbs]

I think there is no use case to call this overload with a nullopt for masterkey.

Consider combining the two overloads:

    /**
     * @brief Create a collection with client-side-encryption enabled, automatically filling any
     * datakeys for encrypted fields.
     *
     * @param db The database in which the collection will be created
     * @param coll_name The name of the new collection
     * @param options The options for creating the collection. @see database::create_collection
     * @param out_options Output parameter to receive the generated collection options.
     * @param kms_provider The KMS provider to use when creating data encryption keys for the
     * collection's encrypted fields
     * @param masterkey If non-null, specify the masterkey to be used when creating data keys in the
     * collection.
     * @return collection A handle to the newly created collection
     */
    collection create_encrypted_collection(
        const database& db,
        const std::string& coll_name,
        const bsoncxx::document::view& options,
        bsoncxx::document::value& out_options,
        const std::string& kms_provider,
        const stdx::optional<bsoncxx::document::view> masterkey = stdx::nullopt);

Or alternatively: make masterkey non-optional in this overload.

[vector-of-bool]

This is more due to my aversion to defaulted arguments. I don't know if there's precedent in the codebase. Combining them will result in a mostly-equivalent API. I'll combine them for now.

[kevinAlbs]

Suggested change

	bson_init_static(opt_mkey.bson_for_init(), masterkey->data(), masterkey->length());
	opt_mkey.init_from_static(*masterkey);

[kevinAlbs]

Suggested change

	scoped_bson_t coll_opts;
	bson_init_static(coll_opts.bson_for_init(), opts.data(), opts.length());
	scoped_bson_t coll_opts(opts);