Adds a single app in the L5 apptray to import-export contacts

This adds a yad panel from which a user can select to launch either the contacts importer script/app or the contacts exporter script/app in the package librem5-goodies.

This is designed to have a single desktop icon and avoid having 2 desktop app icons in the app tray of the Librem 5: One to import contacts, another to export them.

This merge request also removes the original contacts importer desktop icon.

The desktop icon for the new yead panel uses the same logo as the contacts importer script used to use for a simple reason of recognition, people that have used the package librem5-goodies are used to see that icon for a couple of years now.

This is what it looks like. I invested no time in making it nice visually/UI:

Current limitations:

This new yad panel does not close automagically after a user selects to launch one of the two apps (importer or exporter)

closes: #19 (closed)

/cc @guido.gunther for feedback on this.

Signed-off-by: Joao Azevedo joao.azevedo@puri.sm