Add a licence data file

[nahteb]

• Add a data file for licences
• Add a test to validate the licences in the data file conform to our schema https://github.com/alphagov/data-standards-authority/blob/main/adr/0001-standards-catalogue-data-structure.md

[nahteb]

Last thing, sorry!

Can't see what the new requested change is sorry - think I've addressed the ones that were there?