Solidify both OAuth2 and JWT modules into OAuth2 and deprecate JWT in the future

[pmlopes]

JWTAuth performs a subset of the features OAuth2 module does.

It would be good to just have a single module capable of doing it all with a single source of truth.

This means that OAuth2 could be able to issue tokens if private keys are available and All extensions on JWT should be available on OAuth2.

[pmlopes]

This means that the service proxy interceptors would need to be updated to allow Oauth2 instead of JWT.