Android: implement biometric autentication

[pinpontitit]

Describe the feature you'd like to request

In the extension you implemented "Credentials unlocking" to protect the settings and passphrase. You should the same for the android app

Describe the solution you'd like

You should enable Biometric or password or Pin autentication. I like biometric.

Describe alternatives you've considered

Keep up the good work, I love your app