Improve README.md #89
Description
Update the readme to match the new Palm Tree 2.0 goals. We need to do the following:
- Add a reference to the documentation page (and move all related with that to the site)
- Add the roadmap (v2.0 and more)
- Add a reference to the CONTRIBUTING.md (and move all related with that to these file)
- Explain the project (monorepo) structure.
- Update license and credits info