Simplify Getting Started Device SDK examples

Per @rsdmike - simplify the examples in the Go and C SDK getting started pages:  https://github.com/edgexfoundry/edgex-docs/tree/master/docs_src/getting-started

- Don't use Makefile for Go (simple build and run commands)
- allow the code to be placed anywhere (don't need it in GOPATH)
- shouldn't have to download/clone the SDKs