ISPN-3229 L1 cache entries should not be passivated

* Only passivated owned entries
* Added test for L1 entries not being passivated
ISPN-4652 Passivation with shared CacheLoader is not working properly

* ClusteredConditionalCommandTest covers this change
ISPN-4364 Add documentation for Entry Retriever

* Added documentation for retriever
* Also made sure that filter package is public as it should be
ISPN-4446 Signal components of cache removal

* Since stop() takes no parameters, make the remove cache command
signal components of cache removal before cache stop, so that they can
do their job.