Create admin-app skeleton

- Bundle JS files together with the client/app/ application, for now at
  least.
- Add and call debiki.internal.startup() function.
- Move typedef files up one directory so reachable from admin-app.
Make the settings page work.
Make the special-content page view work, but not saving changes.
Make saving special content work.
Specify fake IP in query string 'fakeIp' param.
Make the moderation view work.
Show page and author name.
Various fixes

Tweak CSS, hide dashboard, use <samp> not <kbd>, fix user link.
Add link from /-/admin/ back to the website.
Merge branch 'topic-angularjs-admin'.