Add host count to location API call
Description of problem:
Currently, the API call to "/api/v2/locations/<id>" shows a lot of info, but does not show the number of hosts associated with the location. This is useful for users who use the API to produce reports on how many systems are in each location.
This info is available via the web UI in the locations page, but in order to get at the same information via the API, you have to do a search for each location and count the results.