Add GUI ability to set "qualify_timeout=xx.y" per AOR or globally

You cannot set the "qualify_timeout=xx.y" for any AOR either per AOR or globally. The default of 3.0 is used and cannot be adjusted.

For CELLULAR BASED endpoints, the the typical response back from an AOR to a 'options' message can take over 3.0 secs, hence the 'ARI interface is constantly generating a 'endpoint_state_change' for all of our cellular endpoints. This also marks the endpoint as offline.

Through extensive testing of stationary and moving cellular endpoints, we have determined that setting the 'qualify_timeout=15.0' is the sweet spot to ensure that the response to the 'options' message is received, and keeps Asterisk from marking the endpoint as offline.

Currently there is no mechanism that works to change the 'qualify_timeout' for an AOR.
A previous ticket was opened https://issues.freepbx.org/browse/FREEPBX-20184 that attempted to set 'qualify_timeout' value via the pjsip.aor_custom.conf or pjsip.aor_custom_post.conf files which were not being read or processed by Asterisk for an AOR.

It was suggested by pramarajan@sangoma.com that a 'feature request' be put in so that the 'qualify_timeout' can be modified by extension or globally in the 'SIP Settings' page(s).