Add side menu

[rinse0ut]

Add side menu for pages which have more than 3 headlines.

The side menu lists and links the headline

eg https://staging.javascript101.co.uk/getting-started#code-editors

[STRAYKR]

What do you have in mind for this Dave? Would it look like a static column on the left with anchor links to the H2 headings?

Pseudo code maybe...

1. grab all H2 headings (somehow maintaining the order)
2. if headingsH2.length > 2, display a full height column on the left
   1. in the column list H2 headings in correct order.
   2. the a tags should link to the relevant headings

[rinse0ut]

Yes that's correct.