Go mod

[jniesen]

Summary of Changes:

• Enables go modules by placing the GO111MODULE=on env var in the Makefile
• Add clean and deps targets to the Makefile
  • clean will run go clean and remove an previously created releases
  • deps will run go mod tidy; go get -u; go mod vendor to
    • remove any no longer needed deps
    • download any deps missing from the dev/build environment
    • populate/update the vendor directory
• Creates a go module for this project, remove Dep files and bring vendor dir under go mod management.

[jniesen]

Failing because of one of these most likely:
golang/go#27925 (comment)
golang/go#29278 (comment)

[americk0]

I'm closing this in favor of #80 which does essentially the same thing. Thank you jniesen for starting this off even if it did take us a year and a half to get back around to