Because:
* We're refactoring our legacy tech stack to our preferred stack by extending settings
This commit:
* Adds a clone-legal-docs script so we always fetch latest rather than pin to commit
* Reworks the 'react groups' into separate server and router files; router.js needs access, but cannot have any reference to route definitions since they now contain server-side logic and imports
* Moves available content-server routes into a separate file that does not import route definitions
* Uses and accounts for the existing regex for legal, legal/terms, and legal/privacy
* Adds two helper packages to render the MDs once fetched
Closes FXA-6131
Lauren Zugai