Migrate the "add-license" script to an eslint plugin

[carterworks]

Description

There was a script (pnpm add-license) that walks through the files and makes sure they have a copyright license. I've converted it to an eslint script.

Related Issue

Motivation and Context

Screenshots (if appropriate):

Checklist:

• I have signed the Adobe Open Source CLA or I'm an Adobe employee.
• I have made any necessary test changes and all tests pass.
• I have run the Sandbox successfully.

[Spencer-Smith]

Is the intent that all files have the same year? Or should the year reflect when the file was added to the project?

[carterworks]

Is the intent that all files have the same year? Or should the year reflect when the file was added to the project?

Legal hasn't really specified which, so prior art is that the license header reflects the year it was added to the project.