Move the Maven Java EE-related configurators over to m2e-wtp

We decided to contribute the JavaEE Maven configurators back to m2e-wtp. This includes :

• JPA configurator
• JAX-RS configurator
• JSF configurator

Things to do :

• We must make sure the code doesn't depend on any JBT dependencies
• change namespace to org.eclipse.m2e.wtp.*
• new Contribution CQ must be created @ eclipse.org
• We need to make the current JBT plugins aware of their new org.eclipse.m2e.wtp counterparts and make the transition as smooth as possible for users (disable JBT plugins if m2e-wtp ones are found, or make the upgrade possible between those plugins)