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)
Nope - helpers for error and OK would neither avoid calling `tput` more times than necessary, nor make it clear what each tput actually does.