Is your feature request related to a problem? Please describe.
I'm an administrator of a server for builders. We often have multiple worlds to work with at a time.

Describe the solution you'd like
Let the plugin backup all the loaded worlds by default, providing blacklist/whitelist mode for filtering worlds needed to backup.

Describe alternatives you've considered
None yet

Additional context
None yet

Will be supported via #82

!target 4.0