Backport Memory Controller and Memory FSM from RTPS/DDS Endpoints to
RTPS Builtin Endpoint.
The Memory is now using a single linked list and the FSM uses Frame Field
Flags.
The main FSM uses check_time to initiate stale checks, and the stale
checks are done in the main FSM.
Testbench was modified to accomodate the changes (Previous L0 Test4 was
removed and integrated in L0 Test 1).
