Prepare v2.0.0

[joewiz]

See eXist-db/existdb-dashboard#15

Steps to prepare this PR:

1. made a clone of the old repo
2. made a commit where everything is deleted
3. added the new repo as a remote, and git fetched it
4. cherry-picked in the history of the new repo
5. rebased to squash the commit where i deleted everything with the first commit from the new repo

Yet to do:

6. create new tags for the new repo history which have a different set of tag names e.g. 2.0.0-RC1, 2.0.0-RC2, etc etc