res_pjsip: Add "like" processing to pjsip list and show commands

Add the ability to filter output from pjsip list and show commands
using the "like" predicate like chan_sip.

For endpoints, aors, auths, registrations, identifyies and transports,
the modification was a simple change of an ast_sorcery_retrieve_by_fields
call to ast_sorcery_retrieve_by_regex.  For channels and contacts a
little more work had to be done because neither of those objects are
true sorcery objects.  That was just removing the non-matching object
from the final container.  Of course, a little extra plumbing in the
common pjsip_cli code was needed to parse the "like" and pass the regex
to the get_container callbacks.

Some of the get_container code in res_pjsip_endpoint_identifier was also
refactored for simplicity.

ASTERISK-25477 #close
Reported by: Bryant Zimmerman
Tested by: George Joseph

Change-Id: I646d9326b778aac26bb3e2bcd7fa1346d24434f1

include/asterisk/res_pjsip_cli.h

@@ -61,7 +61,7 @@ struct ast_sip_cli_formatter_entry {
 	/*! The callback used to print the details of the object. */
 	ao2_callback_fn *print_body;
 	/*! The function used to retrieve a container of all objects of this type. */
-	struct ao2_container *(* get_container)(void);
+	struct ao2_container *(* get_container)(const char *regex);
 	/*! The function used to iterate over a container of objects. */
 	int (* iterate)(void *container, ao2_callback_fn callback, void *args);
 	/*! The function used to retrieve a specific object from it's container. */