Use strong encryption in Android KeyStore

[MuntashirAkon]

Investigate and provide options to configure the following security features for the Android KeyStore:

• Use StrongBox when possible
• Require device unlock for operation
• Require user authentication
• Require user confirmation

In App Manager, Android KeyStore is used to encrypt/decrypt the password (the decrypted password is always cleared from memory after each operation) for the BKS KeyStore internally used by Android. Therefore, it plays a very important role if the user has encrypted backups present or use a custom signing key.