Rename index.md to README.md

[manisha-11-dev]

What does this PR do?

Where should the reviewer start?

How should this PR be tested?

Any background context you want to provide?

What are the relevant issues?

[You can link directly to issues by entering # then the number of the issue, for example, #3 links to issue 3]

Screenshots (if appropriate)

Questions:

• Do the docs need to be updated?
• Does this PR add new (Python) dependencies?