res_pjsip_phoneprov_provider: Provides pjsip integration with res_phoneprov

This module allows res_pjsip to integrate with res_phoneprov.  It handles
the pjsip 'phoneprov' object type.

Tested-by: George Joseph
Review: https://reviewboard.asterisk.org/r/3976/
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Merged revisions 425007 from http://svn.asterisk.org/svn/asterisk/branches/12
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Merged revisions 425008 from http://svn.asterisk.org/svn/asterisk/branches/13


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@425009 65c4cc65-6c06-0410-ace0-fbb531ad65f3