Dependency Licensing Improvements

[ssddanbrown]

This PR aims to improve the transparency & clarity of the project dependencies and their licenses, and provides a standard & direct manner of attribution across all project dependencies.

Changes

• Script listing of PHP dep licenses
• Script listing of JS dep licenses
• Add overall licensing info page, with other details for libraries not listed via direct deps like:
  • PHP
  • TinyMCE
  • Material Icons
  • Extract text to translations (Titles/into text, not body content).
  • Add tests to cover (Page exists, Link to page)
• Add neatly into app somewhere (Below version information)
• Add reference to license/attribution list in built source files
• Update licensing/attribution info in readme to refer to new files
• Build updating of deps lists into process somehow.
  • Added a composer command, which is added to release steps.