Pattern for password generator

### Checks

- [x] I have read the Wiki, searched the open issues, and still think this is a new feature.

### Describe the solution you'd like:

Google play user request :
Add the ability to generate passwords based on specific pattern.
For example AAAA-AAAA-AAAA-AAAA where A is any Upper/low letter or digit

The issue names no file, test, or entry point. Start by locating the existing password-generation flow in the Android application and clarify how pattern characters such as `A` should be interpreted and exposed to users. Done means generating passwords that follow a requested pattern such as `AAAA-AAAA-AAAA-AAAA`.

Written by the indexing model from the issue text.