Finalize new mechanism for twin creation, now the basis is a .json...

Finalize new mechanism for twin creation, now the basis is a .json configuration file that can be used to restore the exact state of a gosdn network, also many other changes: clab-config deep copy function, switch to using local gnmi-target, add Transpose() function for generating a modified sdnconfig struct, remove UploadClabConig() (was based on wrong understanding of configurationmanagement service)