Cleaning up repository

[jotelha]

Earlier, I have suggested the creation of https://github.com/livMatS/dserver-minimal as a meta package for installing the triptych of lookup server core, search and retrieve plugins. I would also like to move other clutter as much as possible to that repository, in particular

• all docker-specific content below docker
• anything related to running a development setup (content of devel and wsgi.py)

Also, I would like to remove

• JOSS paper stub. With the PLOS One submission almost through, I don't think we submit a JOSS article on the core dtool-lookup-server (might think about doing so for the webapp at some point)
• .travis.yaml
• anything within provision
• anythin within registration_utils

I have never used anything from the latter two subfolders. @tjelvar-olsson do you think we can drop them? Are you fine with dropping the .travis.yaml, or are you still running travis CI on the repo somewhere?