Add debug switch and API endpoint to stop server when in debug mode.

src/test/json/strawboss.config.json

@@ -1,6 +1,7 @@
 {
   "artifactsRepo": "artifacts",
   "authSecret": "change me",
+  "debug": true,
   "users": [
     { "name": "bob@builder.com", "hashedPwd": "testvalue" },
     { "name": "sam@sousa.com", "hashedPwd": "testvalue" }