Add markdownlint GitHub Action
Add markdownlint GitHub Action

Setup https://github.com/marketplace/actions/markdownlint-mdl-action for
automatic markdown linting.

Signed-off-by: Till Maas <279a4cf6d7f8da1ddc113bb946b9273d9d938683@till.name>

linux-system-roles/network,linux-system-roles/network,linux-system-roles/network