[11.x] Allow using custom authorization validator

[hafezdivandari]

Oauth2 Server allows passing a custom authorization validator (instance of AuthorizationValidatorInterface) to the constructor of ResourceServer class or pass null to use the default BearerTokenValidator.

Devs usually override BearerTokenValidator class to add additional params to the request when validating the token with custom claims, e.g. as this PR intends to make this easier:

• Add method to facilitate BearerTokenValidator override when you want to append data to the jwt token thephpleague/oauth2-server#851

Or as mentioned here:

• Ability to extend the JWT token with information thephpleague/oauth2-server#885 (comment)

This PR allows using custom authorization validator.

[taylorotwell]

I'm getting a bit weary of all the Passport deep customization PRs.

[parallels999]

I really need this 😢