I am fighting with exactly the same topic, and found a Tarball, but get always the information that some files are missing.
Get Plugin from https://github.com/tvheadend/tvheadend/archive/v4.1.tar.gz
Load Plugin from tar.gz
Installing Plugin tvheadend-4.1
Controller OR View Files are missing in the Plugin – Install canceled
Do you have any idea how to deal with that issue?