Android: Fix issues with changing resource directory
This MR primarily does two things:
- We disable changing the location of
resourceCacheDb
. - We change the location of installed resources from external storage to internal storage. This fixes a bug where a user can change the resource location to a different path and things would still work. This also prevents cases where user would delete the installed resource and then things wouldn't open unless the user reinstalled Krita.
There's also a commit adding a button to restore default resource path on Android, since there isn't a way to set it back to the default path (except typing it out manually).