New script to check for SLIM standards compliance

[riverma]

Purpose

• A new script and markdown rendering of compliance against SLIM standards, sorted as a leaderboard table.

  Proposed Changes

• [ADD] Script and README for producing leaderboard table
• [ADD] Missing repo files like contributing guide and code of conduct
• [CHANGE] README to be more compliant with SLIM

  Issues

• N/A

  Testing

• See example rendering of leaderboard table created here: https://github.com/unity-sds/unity-project-management/blob/5a4951d5003ef1565691b3f8617ffe53f28ab308/standards-compliance/leaderboard.md