steps: renamed '* Add a new XY' steps

MR for issue#36 (renaming steps).

From:

* Add a new connection of type "bridge" named "bridge0" for device "bridge0" and options "opts"
* Add a new interface of type "dummy" named "dummy0" with options "opts"
* Add a new network namespace named "ns1"

To:

* Add "bridge" connection named "bridge0" for device "bridge0" with options "opts"
* Create "dummy" device named "dummy0" with options "opts"
* Add namespace "ns1" with options "opts"

parts named "xy", for device "xy" (only for connecions) and with options "opts" (for all) can be omitted. If omitted, you will have to delete them manually afterwards (with tags, etc.).