Make the ee subsystem dependency on the JBoss fork of Jakarta EL optional

The ee subsystem has a hard dependency on the JBoss fork of Jakarta EL. This exists to integrate with some performance improvement caching logic in the JBoss fork. Make this an optional dependency.

There's been some discussion of whether the caching logic is needed or whether it can be moved out of our EL fork. It's not my intent with this issue to say anything about that, neither for nor against. I just want to make not using the fork an option, so we can do development work toward EE 11 support without blocking on making a new fork available.

Even if in the end we create an updated fork for EE 11, the change I have in mind seems like a good one, as it more loosely couples the subsystem to a particular implementation detail.

[1] https://wildfly.zulipchat.com/#narrow/stream/242838-Jakarta-EE/topic/Expression.20Language.206.2E0