Promote Golang code to the root of the repo

- That's where the code is expected to be
- The only reason the code was buried two directories down was because
  it was originally a BOSH release
- There hasn't been a BOSH release in over two years; last one was Feb
  26, 2022
- Other than a slight adjustment to the relative location of
  `blocklist.txt` file in the integration tests, there were no other
  changes

tools.go

@@ -0,0 +1,6 @@
+//go:generate go install github.com/onsi/ginkgo/v2/ginkgo
+
+package main
+
+// This file imports packages that are used when running go generate, or used
+// during the development process but not otherwise depended on by built code.