MediaWiki on docs.webplatform.org/test upgraded

TLDR: I've upgraded MediaWiki on test. Please browse around, try some
edits, create some pages, delete some pages, etc.. Let me know if anything
isn't working as intended.

Full version:

MediaWiki on test was upgraded to 1.22wmf5, a Wikimedia release branch. We
were using a much older Wikimedia release branch previously. Please test
this out. We'll be upgrading current soon. I'll send a followup email with
an upgrade date.

I disabled the following extensions since they were unused and unmaintained:

  ClickTracking
  UserDailyContribs

Most extension we use are written by Wikimedia foundation and were upgraded
automatically since we are using their release branches. They are known to
work well with this version of MediaWiki.

I also upgraded a few extensions that are generally well known to work with
new versions of MediaWiki:

  AdminLinks
  SemanticInternalObjects
  LookupUser
  SubPageList

The following extensions were left at their current version and were copied
in from current:

  SocialProfile
  NoTOC
  NewSignupPage
  TopicTitle
  StringFunctionsEscaped
  Edit Section Link Icon
  Comments
  WebPlatformSearchAutocomplete
  WebplatformSectionCommentsSMW
  Breadcrumb Menus
  CompaTables  skins/webplatform
  skins/WebPlatform.*

There was one extension that was modified locally:

  ConfirmEdit/WpdCaptcha.*

^^ We definitely shouldn't be doing this. That code should be upstreamed to
the extension, we should be adding a submodule to it, or we should fork the
extension.

- Ryan