Updates the docs to work with the website repo - mainly
relative link updates.
Adds a menu.yaml file to build the sidebar menu (no longer
using front matter weight).
Adds a new requirements page to the installation docs.
Wanted/needed some place to document known browser
issues and thought that adding this missing page together
with OS, hardware, database and browser requirements
would be a good thing.
Fix: move 6.4 section in upgrade notes further down.
Fixes#16487
Ref #18690
* Fix: Upgrade hugo wip
* Chore: Rename index to _index for latest hugo
* Chore: Use relative refs, no starting slash
* Feat: Add possibility to mount layouts from grafana.org project
