Bringing the window to the foreground when it's a GtkPlug causes
the main dialog window contents to appear as a floating window. So
let's not do that.

When the device-id is selected after the window is open, switch
to the devices tab and select it.

When the settings app is launched after it's already shown, present
it rather than launching a new one.

Just create an activate action to perform the default action on
the primary instance, also don't create additional windows. We
need to make the settings dialog take an update for when device
icons are clicked in the panel plugin.

We don't want the single app logic for settings because it can be
a normal dialog and plugged into the settings manager at the same
time.

This patch adds actions to map the existing cli options. It allows
the settings dialog to be embedded as a plug and the device-id
mapping for the devices tab. Might need to rework the settings
app a little so it can active the device item rather than launch
a new window.

This changes the settings app to use GtkApplication to handle
process uniqueness rather than our custom version. Currently,
the command line doesn't get handeled properly so it doesn't plug
and the plugin doesn't popup the correct device item.