Doc/version fixes for 0.7.0 release

* Bump the snapshot version to 0.7
* Drop `readme.md` docs in favor of getting started guides and the website
* Bump installation versions to 0.7.0-RC2
* Shed tears at the beautiful release.

Review by @muuki88 @aparkinson and/or @kardapoltsev 

(Also, since we don't have an ML ->  Votes to make @kardapoltsev another committer.  +1 from me, based on his work (26 commits / 15 PRs) for this release)