LPS-49136 SF, use LowLevelCache instead of EhcachePortalCache
LPS-49136 Rename MVCCEhcachePortalCacheFactory to MVCCPortalCacheFactory, no changes.
LPS-49136 Rename MVCCEhcachePortalCacheTest and its unit test, no changes.
LPS-49136 Move classes about mvcc out of ehcache package, no changes.
LPS-49136 Rename EhcacheStreamBootstrapHelpUtil to StreamBootstrapHelpUtil, no changes.
LPS-49136 Move bootstrap classes out of ehcache package, will decouple it and ehcahe completely later, no changes.