feat(IDX): create bot check code

[cgundy]

This PR creates the code for checking the list of approved files that the bot is allowed to edit. This is how it will work:

• in each public repo there will be a file .github/repo_policies/bot_approved_files.json containing a list of files changed by the bot
• load this file
• check the changed files in the PR
• if the changed files are within the approved files pass the workflow, otherwise fail