GTNH custom download

[SgtMate]

Enhancement Type

Improve an existing feature

Describe the enhancement

Enable the GTNH type to start developer and daily versions.
As these are only available via github actions artifacts a feature is required that enables users with higher technical understanding to manually overwrite the output of getGTNHdownloadPath.

[SgtMate]

I'll implement the feature soon. This is just for documentation and discussion purpose.