REFACTORED the Setup Flow Manager so that steps can be started, aborted or a handler can return values by sending signals.

Signed-off-by: Michael Grammling <m.grammling@external.telekom.de>
Merge branch 'master' into huebinding

Signed-off-by: Oliver Libutzki <o.libutzki@external.telekom.de>
Adjustments due to API changes

Signed-off-by: Oliver Libutzki <o.libutzki@external.telekom.de>