Add documentation pages for installing and local development

[PGijsbers]

This PR adds documentation pages for the project, with instructions on installing and developing this project.
It also adds a number of files to create and spin up docker images, to ease the setup of a development environment.
Sorry for including both in the same PR.

Work in progress, to add:

• instructions for setting up a local test database

Postponed for a separate PR:

• configuration options
• Make changing server and database for changing integration tests easier #77
• Add instructions for setting up a completely new database #78
• Simplify setup for local development dependencies  #79

Closes #7 #70 #76

[PGijsbers]

Hi @Taniya-Das, could you have a look at the new documentation and identify if there are still any issues with it?
The documentation is already live at https://openml.github.io/server-api/, which will make it easier to use.
Could you try set up a development environment using this documentation? Following the documentation, you should be able to:

• set up a local documentation server, that renders the local version of the documentation.
• set up a local python-based Python server, that connects to a local test database.

You should be able to make changes to either of them and see the servers reflect the changes (e.g., modify a REST API endpoint or change documentation). You should be able to run all unit tests (from a docker container, at least).

I realize that instructions on how to actually contribute by means of adding a new endpoint is underdocumented, but at this point I figured it's better to merge partial progress now as it already is a big chunk of automation and documentation.

[PGijsbers]

Merging this but still really interested in the feedback and I will process that in separate PRs.

[Taniya-Das]

Hi! I have verified the documentation and I could

1. Follow the documentation to set up the development environment.
2. Successfully run the unit tests from the container.
3. Make changes in the docs (added extra texts) and see them on the server.
4. Modify the REST API endpoint (deleted some of the routers) and see the change reflected on the server.

The documentation is clear and easy to follow.
It might to good to include some information about setup using pyenv.
For Contributing -> Development -> YAML validation, we can also add VS code configuration along with Pycharm. In VS code, Settings -> Extensions -> JSON -> Edit in settings.json