Remove bancha CMS template.

The template hasn't been touched since it was added and the project itself hasn't been updated much since then either:

  * http://docs.getbancha.com/basic/changelog.html
  * https://github.com/squallstar/bancha/commits/master

It doesn't look like a lot of people are using this template, so it probably isn't the best fit for this collection. I'll leave this open for a while in case anyone objects.

/cc @squallstar who first introduced it in #314