What does this MR do?
Updates all installation documentation files with a link to Runners documentation where it is described how to obtain the registration token.
Why was this MR needed?
Are there points in the code the reviewer needs to double check?
Does this MR meet the acceptance criteria?
Added for this feature/bug
All builds are passing
Branch has no merge conflicts with
master(if you do - rebase it please)
What are the relevant issue numbers?
Replaces !126 (closed)