This PR will be the first step to migrate into the core language (actually JavaScript) into TypeScript, as mentionned in issue #66.
The goal of this PR is to just being able to run ts-node in developer environment, the code still need to be cleaned though (which will be done during the next steps).

Here is the tests I have done and work

• Creating a new user
• Deleting an user (from itself or from an admin)
• Creating a new server
• Managing a server (adding an archive exercises.zip, creating groups)
• Launching a Learn-OCaml instance server
• Checking if the instance actually work
• Deleting a server

These tests will be done from an user and from an admin:

• Changing a password
• Disable / activate an user
• Authorize an user
• Stopping a server
• Downloading a server
• Generate and retrieving a teacher token

I will update the list of tests if I have missed some.