[Feature] CLI README

[hjoaquim]

1. Why? (1-3 sentences or a bullet point list):

   • CLI needs a proper README to be displayed in PyPI.

2. What? (1-3 sentences or a bullet point list):

   • Remove CONTRIBUTING: the expectation is that contributors flow into the Platform and not the CLI.
   • Create a minimal README for the CLI that follows the same structure as the Platform and point mostly to the docs website.
   • Updates urls on the Platform README

3. Impact (1-2 sentences or a bullet point list):

   • NA

4. Testing Done:

   • Check cli/README.md