* Add Grandstream Headset/Speaker Ring
Add variable to choose whether the speaker rings with the headset.
* Add Speaker Only option
Add note that speaker only is supported with a value of 2.
There was an illogical if/else statement that the "else" condition would always set a null value, so it didn't really matter. Re-wrote it to properly filter if the transport is set to dns srv and not affix the SIP Port to the server address.
Hide the other connected party on the BLF of supported phones. When not hidden a busy BLF will show the other connected party/sttaus of the call by flashing back and forth between the BLF label and the caller ID.
It also impacts the park buttons, but they typically only show the word "park" because of the character limitations.
Also did more effective find/replace for the distnctive ring variables with regex!
Fix config URL so that the phones don't get an invalid URL when $domain_name is unset. They would previously receive `/app/provision` with no domain/ip included, which makes the phone unable to provision again once they have been added to the Devices page without manually re-setting the config URL or factory defaulting the device.
The alternative solution is that the PHP code could always ensure that the $domain_name variable is set even if the device doesn't exist. My suggestion is to see if it can be set to the same domain/IP as the original provision request from this unconfigured device
