Move most .md into docs/

[meganrm]

Description

I think it's pretty standard to put things like CONTRIBUTING and LICENSE in docs/. Github will still find them and it makes the repo a lot cleaner

@toloudis

[toloudis]

I will propose a PR on bitbucket to get feedback from the rest of SW team and add you. I think putting in the .github folder might be better than docs just because docs is very likely to have a bunch of actual documentation in it.

[toloudis]

For background, this was the source of the layout as implemented here:
https://github.com/creativecommons/.github

https://opensource.creativecommons.org/contributing-code/github-repo-guidelines/

https://github.com/kmindi/special-files-in-repository-root