Be able to specify compression level for save backups as configurable parameter

[DazedNConfused-]

Title mostly. As saves increase in size, the time required to make the backups (unsurprisingly) increases. The fact that the backup manager relies on the highest possible compression contributes to the "slowness".

It would be a nice QoL enhancement that this compression level could be specified by the user, so he may be able to select "store"-level compression and have blazing fast backups.