do all sip registry parsing before transmit_register

do all sip registry parsing before transmit_register

This patch breaks up every part of the sip registry string during
config parsing and removes all parsing from transmit_register().
Thanks to Nick_Lewis for contributing this patch!

(closes issue #14331)
Reported by: Nick_Lewis
Patches:
      chan_sip.c-domparse.patch uploaded by Nick Lewis (license 657)
      chan_sip.c.patch uploaded by Nick Lewis (license 657)
      chan_sip.c.domainparse3.patch uploaded by Nick Lewis (license 657)
      chan_sip.c-domparse4.patch uploaded by Nick Lewis (license 657)
      chan_sip.c-domparse5.patch uploaded by Nick Lewis (license 657)
      nicklewispatch.diff uploaded by dvossel (license 671)
Tested by: Nick_Lewis, dvossel

Review: https://reviewboard.asterisk.org/r/628/

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@266090 65c4cc65-6c06-0410-ace0-fbb531ad65f3