Separate concerns to Affinder/Detectors to handle the logic for using activity info

[youralien]

See imports/startup/server/router.js for the FIXME. At the time of writing, all movement in vehicle / on bike will not register a location update. This leads to

1. No location logs when people are in this state
2. Muddling concerns of what Affinder/Detectors are responsible for.

The benefit of separating them would be

1. Detectors that can use this activity information. This might make nice experiences like this one: