Docsite: inconsistency between landing page, submenus and pages

[june-andronick]

(This may wait for the Information Architecture feedback first)

• The landing page has a nice overview but it's not clear that this is just a subset of the docsite content. We should make that clear.

• The order and titles on the landing page and the submenus should be made consistent to avoid confusion. E.g.

  • "Building Dependencies" vs "Set up your machine" vs "Host dependencies"
  • "Hardware and Target platforms" vs "Supported hardware" vs "Supported Platforms"
  • "Contributing" on the landing page goes to the "Processes" page and the "Contributing processes" goes to the "Contributing" page
  • ...

• The Grouping should be consistent; namely "The source code" appears in "Getting started" in the landing page but belongs to "Contributing" submenu

• the "Roles" page appears in the landing page but not in the submenus. There's a question on location of this page versus having it on the website with the TSC information (see also issue 309 on website)

• All the links from the tutorial section on the landing page are wrong, going to the same root Tutorials page (#206)