ADHOC: Add license

[sfong-roblox]

What problem are we solving?

Doesn't have license in files and in README

How are we solving the problem?

Adding the license per legal's advice

After everything is approved, we typically release under MIT.

Approval checklist

By approving this PR, you confirm with me that the following are true:

• We have all rights to release it, i.e., we wrote it all so we own it all.
• The release has been reviewed and approved at the VP level. We want to be sure that the business justification for the release has been vetted. (This will be the last of the checklist)
• There are no potential Roblox patents or inventions included in the release and no patent claims threatened against the released code.
• There are no trade secrets or other sensitive information included in the release.
• There is no strong encryption in functionality associated with the release.

Checks

Please check these off before promoting the pull request to non-draft status.

• All CI checks are green.
• I have reviewed the proposed changes myself.