[draft][OxCaml] Tutorial for library parameter

[maiste]

This PR is not ready for review. It is a way to share with @art-w the advancement regarding the documentation of library_parameter.

The tutorial aims to follow a simple flow to go through all the possibilities provided by parameterized libraries. It covers the entire "diamond" of the parameterized library, i.e.:

    parameter
   /         \
implement   parameterized
   \         /
    instance

Right now, the PR covers:

• Setting up a project
• Writing a parameter
• Writing the implementation of the parameter

The remaining part are:

• Writing a parameterized library
• Instantiate a parameterized library

The rest of the work is subject to modification as it is currently the first draft.

[Sudha247]

@maiste is it ok if I push to this branch directly?

[maiste]

Yes it that exactly the purpose of this PR 😄