Possibility to set the "lock after" timeout per vault

## Issue Checklist

Before creating a new issue make sure that you
- [x] searched existing (and closed) issues: https://github.com/cryptomator/cryptomator-android/issues
- [x] searched the knowledge base: https://community.cryptomator.org/c/kb
- [x] have read the support guide: https://github.com/cryptomator/cryptomator-android/blob/master/SUPPORT.md
- [x] have read the contribution guide: https://github.com/cryptomator/cryptomator-android/blob/master/CONTRIBUTING.md
- [x] have read the Code of Conduct: https://github.com/cryptomator/cryptomator-android/blob/master/CODE_OF_CONDUCT.md

## Basic Info

I'm using Android in version: `9`

I'm running Cryptomator in version: `1.4.3-rc1`

## Description

Since Cryptomator finally has the photo sync integrated it would probably would make sense to have _different_ timeout settings per vault.
Because it would probably make sense to have long or no timeouts for photos (i.e. syncing a lot of images in holidays without risking losing them on stolen/broken phones).
I don't want to have a long or no timeout on other, more sensible, data or vaults though.