Support queries via posts
Created by: davecromberge
The length of the query sometimes causes a GET request to exceed a maximum length for a url. For such cases, this PR allows an alternative - POST a request where the request body consists of the query. At this time, two content-types are supported - namely:
plain/text application/x-www-form-urlencoded
In the case where requests are sent in unsupported types, a 415 response code is returned.