Merge branch 'refactor' into 'develop'

Programming.md

build/cd/deploy.go

build/ci/.golangci-config/.golangci.yml

build/ci/.test.yml

cli/get.go

cli/subscribe.go

cmd/root.go

controller.go

controller_test.go

gosdn.png

gosdn.puml

http.go

http_test.go

initialise_test.go

nucleus/change.go

nucleus/change_test.go

nucleus/device.go

nucleus/errors/errors.go

nucleus/gnmi_transport.go

nucleus/initialise_test.go