Bugfixes, HA Support & Output Improvement

Bugfixes:
- The program is now checking, if a node is having the "crowbar"
role. If so, the node will stay online after executing the script.
- HA will be now supported

Minor changes:
- Output improving with colors for a better overview.
- Added a main shutdown script (shutdown.sh)
Use temporary variables to avoid calling `tput` more times than necessary, and to make it clear what each `tput` actually does:

    RED="$(tput setaf 1)"
    GREEN="$(tput setaf 2)"
    RESET="$(tput sgr0)"
    ...
    STATUS="${GREEN}done${RESET}"