Adds an API access point for the /exchanges route.
Adds an API access point for the /exchanges route.

This commit is part of patch series where we move exchange
capabilities from one big /exchanges.js file to their
respective js files.

BarnumD/gekko,BarnumD/gekko,pprados/gekko,nourchawich/gekko,generalectric/gekko,askmike/gekko,BarnumD/gekko,generalectric/gekko,nourchawich/gekko,WXLWEB/gekko,generalectric/gekko,nourchawich/gekko,WXLWEB/gekko,pprados/gekko,pprados/gekko,askmike/gekko,askmike/gekko,WXLWEB/gekko