Add support for deriving json schema for encrypted properties.

[christophstrobl]

This issue aims toward support for creating a MongoJsonSchema containing encrypted fields for a given type based on mapping metadata. Currently encrypted fields can only be defined manually via the MongoJsonSchemaBuilder.

 MongoJsonSchema.builder()
    .properties(
        encrypted(string("ssn"))
            .algorithm("AEAD_AES_256_CBC_HMAC_SHA_512-Deterministic")
            .keyId("...")
	)

An @Encrypted annotation should allow to derive required encryptMetadata and encrypt properties within a given (mapping)context.

@Document
@Encrypted(keyId = "...")
static class Patient {

    // ...

    @Encrypted(algorithm = "AEAD_AES_256_CBC_HMAC_SHA_512-Deterministic")
    private Integer ssn;

}

MongoJsonSchemaCreator schemaCreator = MongoJsonSchemaCreator.create(mappingContext);
MongoJsonSchema patientSchema = schemaCreator
    .filter(MongoJsonSchemaCreator.encryptedOnly())
    .createSchemaFor(Patient.class);

[jagadeeshkoka]

Can I work on this one ?

[christophstrobl]

@jagadeeshkoka there's a PR (#3801). Please feel free to add your thoughts.