Replace DataStoreCache with DataObjectCache in itm-impl

Replace DataStoreCache with DataObjectCache in itm-impl

There were 4 different caches to convert. 2 of them,
TunnelMonitorParams and TunnelMonitorInterval, are singleton
DataObjects use for global tunnel monitorng configuration.
These seem to be condidates for clustered-app-config however
dynamic updates would restrart the BP container but it doesn't
appear itm-impl is ready for that. So to preserve existing
behavior, they're DataObjectCache instances local to a new
TunnelMonitoringConfig class.

The other 2 caches were replaced by DataObjectCache subclasses,
DPNTEPsInfoCache and TunnelStateCache, and injected where needed.

Change-Id: I4e4ed505fa46a5af05086436a7593d92d2bdb56c
Signed-off-by: Tom Pantelis <tompantelis@gmail.com>