MODE-1770 Added PESSIMISTIC locking to the default, in-memory Infinispan configuration

The LocalEnvironment class and its [createDefaultConfiguration()](https://github.com/ModeShape/modeshape/blob/db418d6163830608c4a8e764c33f820f374c5a56/modeshape-jcr/src/main/java/org/modeshape/jcr/LocalEnvironment.java#L216) method are used to create the default cache configurations for in-memory content. This method does set up the transactional behavior, but does not set the locking. Therefore, I think it is prudent to add code to this method that sets up the LockingMode of PESSIMISTIC.

Verified that this has no negative effect on the tests.