Make a /docs a Git subtree

[bep]

While the splitting of docs => hugoDocs was a good idea, and we should continue with that, the submodule approach has some major flaws:

1. It's not possible to create an "atomic PR" with both code and documentation changes.
2. Old PRs that does the above is no longer easily mergeable.
3. This change made the release process more complex than needed.

Maybe Git subtrees?

https://developer.atlassian.com/blog/2015/05/the-power-of-git-subtree/

Help/suggestions welcome. I think we got to fix this sooner than later.

/cc @digitalcraftsman @spf13 @moorereason @anthonyfok

[bep]

This article describes it pretty well:

https://medium.com/@v/git-subtrees-a-tutorial-6ff568381844

[bep]

Notes:

git remote add docs git@github.com:gohugoio/hugoDocs.git 
git subtree add --prefix=docs/ docs master --squash

Pulling changes should be:

git subtree pull --prefix=docs/ docs master --squash

@digitalcraftsman we should mostly do changes in hugoDocs, but I guess we can synch both ways if needed (use case: PRs with docs changes). We should live with this for a while to test it out and update contrib. guide.

[digitalcraftsman]

@bep re the use of the master branch: please have a look at gohugoio/hugoDocs#19 (comment).

[github-actions]

This issue has been automatically locked since there has not been any recent activity after it was closed. Please open a new issue for related bugs.