Release version 3.14

[mueller-ma]

Pre-release checklist

• [x] Check for major crashes in latest stable version
• [x] Check for major crashes in beta versions since last stable version
• [x] Merge new translations

Release notes

• Allow configuration of Main UI start page
• Add screensaver feature

Blocking issues/PRs

None

Post-release checklist

• [x] Release in Play Store in the open test track
• [x] Release in Play Store to 20%
• [x] Release in Play Store to 50%
• [ ] Release in Play Store to 100%
• [ ] Check for new crashes