Add echo CmdStager
Add documentatio to the mixin
Use shellwords, as recommended by @jvennix-r7
Ensures termination of inner while loop and cleans up #map.
* Tested working against ubuntu target using the sshexec test script.
Land @jvennix-r7 changes
Fix @todb-r7 feedback
Land #2371, echo -e cmd stager
Fix my own cleanup