res_pjsip: Allow configuration of endpoint identifier query order

res_pjsip: Allow configuration of endpoint identifier query order

Updated some documentation stating that endpoint identifiers registered without
a name are place at the front of the lookup list. Also renamed register method
'ast_sip_register_endpoint_identifier_by_name' to
'ast_sip_register_endpoint_identifier_with_name'

ASTERISK-24840
Reported by: Mark Michelson
........

Merged revisions 433031 from http://svn.asterisk.org/svn/asterisk/branches/13

git-svn-id: https://origsvn.digium.com/svn/asterisk/certified/branches/13.1@433034 65c4cc65-6c06-0410-ace0-fbb531ad65f3