Split plugins config dir and data dir

Is your feature request related to a problem?

Having a clean separation between data and configurations.

Describe the solution you'd like.

The idea is to have a separation between the plugins config directory and the data directory.

In Minecraft 26.1 a refactoring is done where the data is saved.
So basically the data can be saved under data/<namespace>/ following the new structure suggested by Minecraft. e.g.:

data/fastasyncworldedit/editsessions/2c771d16-f492-4f7a-adb7-61c38a9c9bfb.session
data/fastasyncworldedit/editsessions/98bec4ae-53e1-4031-8268-4cda1efc9d5b.session

Data saved in the data folder is now namespaced
This means that all that data will now be stored in a namespace subfolder in the corresponding data folder
All existing vanilla data files have been moved accordingly
Example: data/scoreboard.dat -> data/minecraft/scoreboard.dat
Command storage is now stored in namespace subfolders instead of having a namespace suffix
Example: data/command_storage_foo.dat -> data/foo/command_storage.dat
chunks.dat has been renamed to chunk_tickets.dat
Data for maps is now stored in the data/minecraft/maps subfolder
Map index files have been renamed to only the number
Example: map_1.dat -> 1.dat
idcounts.dat has been renamed to last_id.dat
There is no more raids_end.dat special case
The End now uses raids.dat as well

https://www.minecraft.net/en-us/article/minecraft-26-1-snapshot-6

Describe alternatives you've considered.

Resolving the path to a separate plugin defined data dir myself.
The above is just good practices separating data and configurations.

Other

No response

Start by reviewing the Minecraft 26.1 Snapshot 6 reference linked in the issue and the server's existing plugin configuration and data-directory handling. Define the affected API or entry points before implementation; done means plugin configuration and namespaced plugin data are stored separately, following the requested data// structure.