Add function to clear cache in editor

[Muzz]

Issue description:

One of the big issues we constantly run into is broken asset references or things in general being broken because pulling assets from git does not force the cache to update properly. This means that we need to manually clear cache whenever we pull, or we run into random issues. Forgetting to do this has meant we've wasted a lot of time trying to work out why things are broken after a pull. It would be good to have a function to totally clear the cache and rebuild in editor from that.

If there is better ways to deal with this, let us know!