[keycloak-dev] jta, emf, db migration

Currently there is some issues with master since I added JTA transactions to the mix * KeycloakDS datasource config now requires jta=false. This breaks backward compatibility and has migration issues. This was done because both RESOURCE_LOCAL EntityManagers and Liquibase (using raw JDBC) cannot function within a JTA transaction. * Our EntityManager implementation is not controlled by JTA. This is not great as the db connection cannot be involved with XA, especially if another external transaction resource is involved when doing events and/or user federation. To do this I had to do some things that may be a little weird. * Entity Manager is now JTA managed if JTA exists in the environment keycloak is running in. The side effect of this is that all interactions with the EntityManager need to happen within a JTA transaction (or you get an exception). * jta=false is reverted in server distribution * All DBLock and Liquibase operations now suspend any existing JTA transaction before executing. You cannot call commit/rollback on a JDBC connection if you are getting a connection from a JTA aware db connection pool and there is a JTA connection active. DBLock calls a rollback() for some reason...if running in JTA, this marks the connection as rolled back and you can't use the connection after that. So basically for DBLock and Liquibase there's a lot of issues with running inside a JTA transaction. Honestly, this code can and should be refactored into different providers (i.e. a DBMigrationProvider), but I've got so many other things I need to refactor right now I'm going to put this on the back burner. Bill