Add a config flag to the backup-script to not backup certain files

[Stefan240]

This is just a quick discussion I wanted to open about this package. First: Thank you for making misskey so easily accessiable with yunohost.

basically I would like to ask if it would be possible to allow the exclusion of certain folders in the backup script via a config-flag perhaps. Maybe something like described here: https://yunohost.org/ar/backup/include_exclude_files#do-not-backup-large-amounts-of-data

There should be an option to exclude misskeys "files" directory when updating, since it can get quite large with time (mine is about 40GB right now) making updating a slow and tedious process to deal with.

Is there something I can do so the files directory does not get backed up when updating misskey via the package?