Resolve "Creating a new device with type plugin just returns a normal device"

• This commit is a interim solution that allows to create new devices with the --type plugin flag. The orchestrator will only request capabilities of the provided device and build/return all the necessary files. Therefore the api has been adjusted to allow to 'only' create gostructs and do not fire up a whole csbi.

• Additionaly the issue #176 (closed) has been addressed and the bug while creating multiple cSBIs has been fixed. Appending to the .Methods string of the global SouthboundStruct was the root cause for this bug. Creating a copy of SouthboundStruct and using the copy in the process fixes this issue.

Related Issue

#175 (closed) , #176 (closed)

Closes #175 (closed)