Decommission old GO SDK

[e-backmark-ericsson]

The Go SDKs should be decommissioned as there is a new Go SDK being developed for CDEvents. The PoC in this repo is dependent on that old Go SDK still, so until the PoC is migrated to use the new Go SDK we'd need to keep it here. There is probably no major reason to move the old Go SDK to the cdevents org and migrate the PoC there.