Geo Usage Ping: Track OAuth Access Grants

An easy win is counting the OAuth access grants to geo applications. When you create a geo node, it creates the oauth application and associates it, so we should be able to just look up and count all of the grants. These grants are created whenever the user's session expires on the secondary.

Definition of Done:

• Report count of unique secondary web users per month/all time

Notes:

This won't count every time someone uses a secondary, but it should at least help us determine how many people have logged in to one recently through the UI.