Have an option to only cache blocks in RAM

## Describe your suggestion
Caching seems to have no option for not utilizing hard disk so have add an option for it

## Settings
OnlyCacheFromRam

## Context
Would help people with limited disk space and ram that they dont use

## Final checklist
- [x] I know how to properly use check boxes
- [x] I have not used any OwO's or UwU's in this issue.