Add extension in contact

Add extension-in-contact feature to gateways setting.
https://freeswitch.org/confluence/display/FREESWITCH/Sofia+Gateway+Authentication+Params

By default it is false. Some sip providers require it to be true.

For example, in order to use Telnyx.com AnchorSite manually set to a specific site, for outbound calls, when using user/pass authentication, this must be set to true.

NOTE: freeswitch_form.php is shown as all new because git doesn't appear to be detecting just the one section that was updated. The file is exactly the same as before with the addition of the following.

array (
	gettext ( 'Extension-In-Contact' ),
	array (
		'name' => 'extension-in-contact',
		'class' => 'add_settings' 
	),
	'SELECT',
	'',
	'',
	'tOOL TIP',
	'',
	'',
	'',
	'',
	'set_sip_config_option' 
),

On line 1130

The messages.mo language binary files were updated using this generator.
https://po2mo.net/