Strip white-space
Differentiate ZeroMQ from RAET based installations.

Since the requirements are different, "decide" which to require.
Update install documentation to reflect RAET deps
Document the `--salt-transport` option
Also provide a `pip` example on how to pass the global variable
Merge pull request #13505 from s0undt3ch/hotfix/setup-raet

Differentiate ZeroMQ from RAET based installations