Improve jwt-auth modularization before 3.0.0 release

[sberyozkin]

The old implementation module has just been split on the master branch into common , jwt-build and jwt-auth (which is effectively the old implementation minus the common utility and JWT builder API).
jwt-auth still depends on jwt-build to keep the existing expectations and it also ships the JAX-RS code which is not used by all the integrators.
The proposal is to modularize jwt-auth further before 3.0.0 (MP JWT 1.2) is released :

• move the JAX-RS code into a new jwt-jaxrs module which will depend on jwt-auth
• drop smallrye-jwt-build dependency and let users add it if it is needed (though if we can expect the builder API be eventually standardized then perhaps it would be better to keep this dependency but the users can now easily exclude it if they don't use the builder API - this looks like a better option - otheriwise if we drop it now and then decide to add back then it would be a bit of a mess :-) )

[sberyozkin]

@radcortez FYI, I'm planning to fix this issue before 3.0.0 as well