Chart: Boarding maps to accept filters rather than list of _ids

[am-MongoDB]

The web app's boarding page currently sends a query with an unlimited list of report IDs to be rendered on the map. That breaks limits on the size of http requests.

Instead, we should have server-side Chart logic that takes filter criteria, which it then uses to find all of the documents that should be rendered on the map.

Once that is implemented, raise a web ticket to use the new Chart.