feat: Use multipart formdata to start a job (#3)

- refactor to use fetch API
- convert JSON request to FormData
- add testing framework
- add bundler test

Author: arumsey

.mocharc.json

@@ -0,0 +1,4 @@
+{
+  "spec": "test/**/*.test.js",
+  "loader": "esmock"
+}