Documentation improvements

[turn1a]

A catch-all ticket to gather documentation improvement ideas.

1. Mark code blocks in README.md's Markdown with specific language - you can use

   ```python

   or

   ```yml

   at the beginning of a code block to enable syntax highlighting.

[Galileo-Galilei]

Hello @kaemo, this is the next task I will be working on. I have in mind the following items (in addition to your remark):

• [x] Add community files to enforce collaboration (I will likely stick to github defaults here):

  • [x] Code of conduct
  • [x] Contributing guidelines
  • [x] Issue templates
  • [x] Pull request template

• [x] Define a detailed overview of the documentation structure.

  • [x] Introduction
    • [X] introduction.md : Description of kedro and mlflow, and brief comparison
    • [x] motivation.md : justification for the need of a plugin to fill a gap

• [x] Correct the README which is obsolete since kedro release 0.16.

[Galileo-Galilei]

Update the readme:

• [x] Add a section to warn for the beta status of the plugin (and specify we use SemVer)
• [x] Add a section with comptibiltiy between mlflow, kedro and kedro mlflow different versions
• [x] Move "main contributors" section to the end of the README with the contributing section

[Galileo-Galilei]

It is very common to have some broken links in the documentation. I suggest we:

• [x] add a CI step to check for broken links.