h5p get does not work properly in anonymous docker builds

[kentis]

We have noticed that "h5p get" exclusivly uses ssh-based github urls. This is somewhat challenging when automating h5p builds and deployment using the h5p cli tool. The pull request at: #38 includes a suggestion on alleviating this.

[devland]

h5p-cli core functionality has been rewritten. Try using the new setup flow.