Fix crash when no geo URI activities installed.

When there are no activities that support geo URI installed
on the device, Subsurface companion app will crash with
ActivityNotFoundException.

This patch checks with PackageManager for such situation and
disables "Show on map" menu item if necessary.

Signed-off-by: Sergey Starosek <sergey.starosek@gmail.com>
Signed-off-by: pralonga <aurelien.pralong@gmail.com>
Release 1.7 preparation

Signed-off-by: pralonga <aurelien.pralong@gmail.com>