Is your feature request related to a problem? Please describe.
Sometimes user accidently deleate a board. This removes everything related with the board and a restore is possible, but not very easy because many database entries and (sometimes) files are affceted.
If a board is shared with outhers and they have the right to manage the board, it can be deleted by them.
Sometimes this happes unwanted, because the user just want to get a better overview and since there is no grouping or hiding of boards is possible, the user creates this overview by deleting the board for everyone. Sure it's a fail of the user, but it's very bad to fix this, after it has been deleted.

Describe the solution you'd like
A board should just marked for deletion and the delete job should not run 5 minutes after marked for deletion. Better would be to make this time span configurable, so that a manager or admin can undelete the board without restoring the DB.

Describe alternatives you've considered
Alternative would be, that a deleted board would be exported to a textfile (or json or whatever) on server and could be reimported by admin.