brig check should be ported from 1.x to 2.x

[krancour]

In v1.x, this command (like everything else) would have required direct access to the cluster.

In 2.x, the right thing to do is add an endpoint to the system API that checks on all components and returns their statuses. This was v2.x users who may not have direct access to the underlying cluster can still make determinations about the health of the brigade instance.