sorcery: Add setting object type congestion levels.

Sorcery creates taskprocessors for object types to process object observer
callbacks.  An API call is needed to be able to set the congestion levels
of these taskprocessors for selected object types.

* Updated PJSIP's contact and contact_status sorcery object type observer
default congestion levels based upon stress testing.  Increased the
congestion levels to reduce the potential for bursty register/unregister
and subscribe/unsubscribe activity from triggering the taskprocessor
overload alert.

ASTERISK-26088
Reported by:  Richard Mudgett

Change-Id: I4542e83b556f0714009bfeff89505c801f1218c6