Clarify @RolesAllowed and authorization modules enhancements

[ayoho]

The Security 4.0 release plan mentions two points that don't have further details:

• @RolesAllowed alternative
• Authorization modules

Scott Stark brought this up in the mailing list in July with Arjan providing some links to related questions:

• https://github.com/jakartaee/security/issues/204
• https://stackoverflow.com/questions/27341665/is-it-possible-to-determine-group-membership-of-a-user-on-demand-instead-of-when
• https://arjan-tijms.omnifaces.org/2016/07/simplified-custom-authorization-rules.html

However there still needs to be some specifics provided about what exactly is planned to be enhanced in Security 4.0.

[arjantijms]

Done! Thanks for the reminder :)

[arjantijms]

See https://github.com/jakartaee/security/issues/296 and https://github.com/jakartaee/security/issues/295