This change adds database tables for the PUBLISH support so it
can be configured using realtime. A minor fix to the
res_pjsip_publish_asterisk module was done so that it read the
sorcery configuration from the correct section. Finally the
sample configuration files have been updated.

ASTERISK-26928

Change-Id: I81991ae5c75af98d247f7eacd1c0b0a763675952