When cherry-picking geolocation prerequisites to the certified/18.9
branch, the commit that moved res_pjsip documentation to separate
XML files was cherry-picked after other that assumed it was
already there. This caused a few configuration options to be
dropped from the XML and prevented res_stir_shaken and some
pjsip transports to fail to load.
Those entries are now in their correct spots in pjsip_config.xml.
A housekeeping change was also made to both pjsip_config.xml and
pjsip_manager.xml to add stylesheet and namespace info.
Change-Id: I0ea2eb191e006673f4fa3caafb2edbc92b3e1214