Option --exclude-caches appears to be missing

[Wikinaut]

I cannot find that borg option --exclude-caches to be used by vorta. Was that intended?

See https://borgbackup.readthedocs.io/en/stable/usage/create.html?highlight=exclude%20caches

I suggest to add this as a vorta option which is active by default.

[m3nu]

I'm copying this to #907 to avoid overloading the project with too many open issues. Let's discuss all exclusion improvements there please.

[Wikinaut]

Sehr gut! Really. I like a centralized place for improvements.