Add ability to specify folders to ignore when backing up specific saves

[fennectech]

Is your feature request related to a problem? Please describe.
A clear and concise description of what the problem is. Ex. I'm always frustrated when [...]
Working with minecraft saves takes ages to backup and restore becuase DLC is stored in savedata

Describe the solution you'd like
The ability to specify by config directories within the save container not to be backed up or restored.
Describe alternatives you've considered
I cant think of another way to leave DLC alone when its stored in savedata.

Additional context
the directory /premium_cache is full of flatpack files that total arround a gig on my setup the ability to ignore that directory from my save operations would be great

[fennectech]

Out of that 1.8GB 395, items totalling 196.6 MB (199.1 MB on disk) is actual savedata. The rest could be ignored by ignoring /premium_cache