maint: Add LICENSES dir

[TylerHelmuth]

Which problem is this PR solving?

• Adds LICENSES folder with all required licenses/notices

Short description of the changes

• Adds licenses/notices to LICENSES folder
• Adds a check to the build job that ensures the LICENSES folder is up-to-date.

[kentquirk]

Additional requests:

• Can you add an "update-licenses" Make target also, please, and maybe have the verify task say how to run it?
• Is just stuffing these into our repo enough, or do we also need to attach them to the built artifacts somehow?

[TylerHelmuth]

Can you add an "update-licenses" Make target also, please, and maybe have the verify task say how to run it?

Will do

Is just stuffing these into our repo enough, or do we also need to attach them to the built artifacts somehow?

As I understand it, we do need to update some stuff about our build, mainly some adding some important labels to the image that points back to this folder. I plan to do that in a separate PR.