Fix #14 Remove "Do you like QKSMS?"
Fix #16 Backup not working (disabled)
Fix #13 Replace QKSMS by Message

See merge request !6

1. Remove Invite and Help section
2. Add /e/ specific about menu
3. Mark a few strings not translatable

Remove core-ktx to prevent build failure and remove release signature as platform certificate is used to sign

This should address #1340

Should hopefully address #1340

In case different contacts share the same phone number, the displayed
photo got mixed-up.
This bug was due to the fact that the contact's first phone number was
always used. This commit makes sure we keep using the right combination
of phone/contact.