When opening the user panel we g-c-c performs lots of sync operations that
may cause a noticeable slowdown, especially when a fingerprint device is
available, in fact set_fingerprint_label() call leads to:
- DBus sync request of the system bus
- fprintd dbus-activation
+ This leads to sync opening of all the devices, that might also cause
a slowdown, depending on the devices drivers
- Dbus sync calls to the device to get the list of enrolled fingerprints
Only after we've a reply, we update the g-c-c UI and continue the execution.
The fingerprint dialog code would need some global refactor, but to fix this
without big changes, let's just use GTask that runs a thread in wich we do
all the sync operations, and once done we finally update the widget state.
Switch from GtkBuilder to using GtkTemplate.
Rename .[ch] and .ui files to standard names.
Rename widget IDs to be more readable.
Drop widget IDs that are not used.
Move code into the .ui file that can be.
Connect signals in swapped form.
