main: Libify mgmt with a golang API

This is an initial implementation of a possible golang API. In this
particular version, the *gconfig.GraphConfig data structures are
emitted, instead of possibly building a pgraph. As long as we can
represent any local graph as the data structure, then this is fine!

Is there a way to merge the gconfig Vertex and the pgraph Vertex?

test/test-headerfmt.sh

@@ -11,7 +11,7 @@ done < "$FILE"
 cd "${ROOT}"
 
 find_files() {
-	git ls-files | grep '\.go$'
+	git ls-files | grep '\.go$' | grep -v '^examples/'
 }
 
 bad_files=$(