Fix for libvirt domain listen address
fixes #2562 for libvirt domain listen address
Added Configurable setting to database default_console_address with default of 0 (For backwards compatibility)

This will allow users to customise their defailt libvirt vnc console listen address
fixes #2562 for libvirt domain listen address
Removed Migration in favour of settings helper
fixes #2562 for libvirt domain listen address
Removed Migration in favour of settings helper
Updated update_display call to specify existing listen address for that vm as listen address cannot be updated on the fly
Updated default_console_address to have libvirt in the name, Update the setting to default to 0.0.0.0
Merge branch 'listen_address_fix' into develop