Don't allow comments on documentation pages

We want updates to be done via pull-requests!
Allow side menu to be changed

This is ideal for subcategories (e.g. components).
Make page date optional
Prefix title with subcategory if it is set
Fix indentation
Build better breadcrumbs
add 2 links in the docmenu to see if it works
Edit docmenu a bit
Fix category index using title instead of category

This hasn't caused any issues so far as the category and title have so far always been the same.
Add other documentation page to capture list of older article based documentation
Populate menu links with some example articles

TODO: Refactor existing documentation to fit the menu properly
Clean up documenation menu
Remove garbage script tag
Point at SCDB docs and refer to "configuration modules"
Point at latest version of component docs

TODO: Ensure this is bumped per release
Merge pull request #107 from jrha/doc-index

Restructure documentation