res_pjsip: improve realtime performance on CLI 'pjsip show contacts'

CLI command 'pjsip show contacts' inefficiently make a lot of DB requests.

For example if there are 10k aors then asterisk requests these 10k records
of aor and then does 10k requests of contact - one request per aor.

Even if use 'like <pattern>' the asterisk requests all aor's and contact's
records and then filters them by itself.

This patch gathers contact's container by
- retrieving all dynamic contacts by regex (filtered by reg_server)
- retrieving all aors with permanent contacts
- finally filters container by regex

ASTERISK-28077 #close

Change-Id: Id0ad65d14952a02fb213273a90f3f680a8149618