Move metatool to mt-mods project

[S-S-X]

I think that metatool mod is stable enough to get moved to https://github.com/mt-mods community project.

API has been mostly stable without breaking changes and first official release is out.
Basic framework does have somewhat defined its shape and proved itself through several tool and node updates.

There's still many useless things around API, refactoring and cleanup to do but things seems to work pretty well and so far there's been no problems adding new features or updating smaller details.

[S-S-X]

still many useless things around API, refactoring and cleanup to do

just adding note that I would like to cleanup this stuff before moving this project but not sure if I have time to actually do it, I'll let this sit for a while and see later if there has been any progress. If not then maybe just move as is.