De-emphasise EJB, JNDI, resource-refs, etc in Concurrency #252

The Current concurrency specification is largely based on work from 2002~2004, which was left dormant for well over a decade and then "suddenly" revived where it found itself in a modern world.

As such, Concurrency is rive with things from that ancient time, like EJB, JNDI, resource-refs, etc.

In modern day Jakarta EE programming those things are large de-emphasised in favour of CDI. Specifically, because of all the resource-refs and such, Concurrency would not fit well in the Core Profile and would be largely unusable in MicroProfile environments.

#229 made a start with addressing this, but I would like to take it a step further; deprecate JNDI and resource-refs (including @resource based injection), and make CDI a core requirement. Also strongly de-emphasise using EJB in the TCK for everything, and make CDI beans the default.