Add utility to parse metrics via API

[labkey-chrisj]

We currently support parsing metrics via the UI, but for future reference (and speed/efficiency) it will be desirable to be able to parse metric values directly from JSON as it returns from http://localhost:8080/admin-testMothershipReport.view

[labkey-chrisj]

Notes:

• the getProperty and findObject methods of CommandResponse may provide a pattern by which we can generically pull values out of large/nested JSON maps using jsonPath

Also, getting the JSON for metrics might be as simple as
var command = new SimplePostCommand("admin", "testMothershipReport"); var response= command.execute(createDefaultConnection(), path); var json = new JSONObject(response.getParsedData());