Add a link to all install documentation files describing how to obtain a registration token

Merged Tomasz Maczukin requested to merge update-installation-docs into master

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?

  • Documentation created/updated
  • Tests
    • 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)