Photos Management

### Please agree to the following

- [X] I have searched [existing issues](https://github.com/cryptomator/android/issues?q=) for duplicates
- [X] I agree to follow this project's [Code of Conduct](https://github.com/cryptomator/android/blob/develop/.github/CODE_OF_CONDUCT.md)

### Summary

Introduce a Photos Management feature in the Cryptomator Android app to display photos from the vault similar to Google Photos.

### Motivation

Currently, Cryptomator users have to navigate through folders to view their photos stored in the vault. This can be cumbersome and inefficient, especially for users who store a large number of photos. The proposed feature aims to improve user experience by providing an easy and intuitive way to access and manage photos directly within the app.

### Considered Alternatives

- Using third-party photo management apps to access decrypted photos.

- Manually organizing photos into folders for easier navigation.

However, these alternatives do not provide the seamless integration and ease of use that an in-app photo management feature would offer.

### Anything else?

After unlocking a vault, a new bottom navigation bar should appear at the bottom of the screen. This bar will have two buttons: "Files" and "Photos". The "Photos" section will display all photos in the selected folders of the vault, mimicking the interface and functionality of Google Photos. Users can specify which folders to include in this section through the vault settings.