Update minimum SDK level

[Th3Ph4nt0m]

Our current minimum SDK level is 19. By updating it to 27, we are able to take the following changes:

• App-Lock (Fingerprint)
• Improving Autofill-Support
• Text-Selection (Copy EVA-notices to clipboard)
• App Shortcuts (Long-Press the app for e.g. going directly to the dashboard)
• Prioritized Notifications
• Auto-sizing Text-Views
• Optimizing WebView

[michael-mosler]

Raised level to 25. With 27 we currently would loose a whole bunch of users.