GUI: explorer: Hide upload field when displaying cached report

Signed-off-by: Tim Serong <tserong@suse.com>
GUI: hb_report: Fix localization of close button

Signed-off-by: Tim Serong <tserong@suse.com>
Misc: Move gettext script include to main layout

Signed-off-by: Tim Serong <tserong@suse.com>
GUI: Add Preferences dialog to allow choosing UI language

Signed-off-by: Tim Serong <tserong@suse.com>