Codex has a composer library. Let's try using that for the "create a wiki" form on the Patch Demo main page.

AC:

• Codex added to composer dependencies
• No OOUI form fields in main page
• Updated main JS to support
  • Global patchdemo instance settings
    • Pills for patchsets: make a pill with the gerrit patch title
    • Custom wiki names: show hide/validate
  • Per wiki settings
    • Radio configuration presets: vary checked extensions based on radio button
    • Create a wikifarm: show/hide + change configuration presets