Improve the Multipass cloud-config.txt by using the install.sh script
instead of stale install instructions. This ensures that the latest
release is installed and reduces the number of install instructions we
need to maintain.
Also, improve the instructions for using multipass by including a
one-line command for setting the correct ssh key _and_ starting the VM.
Finally, improve the markdown formatting by indenting the paragraph
bodies of the list items. This ensures that the content is properly
aligned with the bullet list.
Signed-off-by: Lucas Roesler <roesler.lucas@gmail.com>
