Store unsupported OMCI-MEs into DB

Please refer to discussion in VOL-3532:
"The best thing to do in the case of an unsupported class ID (not decoded or vendor specific) is to save it like any other class ID to the MIB data base, but save the attributes past the Entity ID as a binary blob.   In the python version of the openOMCI library omci_cc.py did this in the __decode_unknown_me class.

Probably handling it the same way would be appropriate for the golang version.  For MIB uploads, it is safe just to store it away in the MIB database.  If it is an Alarm or AVC notification, not much can really be done and probably an INFO level debug message can be issued.

Also, in the adapter itself, keeping some statistics on OMCC operation and decode/encode success/failure counts is useful.   This could be published on a kafka bus at a low frequency.  The python version did that as well as some OMCI CC state-change steps.   Came useful during debugging of the adapter to start with and may help during porting of additional ONU vendors."