Remove EJB facade from default distributions

Since we upgraded to JBoss 5, ejb3 support has become a real pain:

• deployment is very slow and eats a lot of memory
• a lot of bugs that we had to walkaround
• application is about twice slower under load when using EJB3

In parallel, we don't really need EJB3 support anymore:

• remoting is done via content-automation
• in specific cases VCS Client/Server mode could be used
• new shell relies on automation
• transaction demarcation is completly managed by Nuxeo

This means we can get ridd of the EJB3 facades:

• remove bundles from default distributions
• double performances under JBoss 5

If needed, we could maintains a compat assembly containing the facacdes?

Associated work includes:

• remove the facades
• be sure to correctly integrate the JCA pooling without using DocumentManagerBean
• check behavior for Rollback in case of runtime errors
• check JPA integraton (i.e. try to get the JPA context from the container now that we can not inject it via EJBContext)