Reorganize entire project

Created a new directory structure to make it more convenient to edit
files locally using the node-google-apps-script package, switched from
a bound to a standalone script for testing as an add-on, removed OAuth
library and related code (not going to implement the features that
required it), updated comments, and started the help document for end
users.

.gitignore

@@ -0,0 +1,2 @@
+.DS_STORE
+gapps.config.json