Use add_arguments_to instead of parameters

This way we have more control - a selector could be used for the
executors.

Signed-off-by: Mate Lakat <mlakat@mlakat.hu>
Remove logserver, fix check connection

Signed-off-by: Mate Lakat <mlakat@mlakat.hu>
Use EXECUTOR_NAMES
Use configuration for ssh key
Do not use tilde
Use /etc/osci/osci.config
Use add_arguments_to
Fix tests
Fix accessing image_name
Activate environment
Add flag to skip status updates
Fix deleteNode call
FIx tests: now using _deleteNode

Signed-off-by: Mate Lakat <mate.lakat@citrix.com>
Fix tests: use label_name instead of image_name

Signed-off-by: Mate Lakat <mate.lakat@citrix.com>
Add purge function
Fix typo