Some more detailed monitoring stuff

Added more monitoring tasks, mostly focused on SQL. Also simplified the HTTP monitor to be parallel and only perform one request (since it will just be trying again almost right away, no need to perform multiple requests.

By far not the end of this :). Just thought I'd throw out what I had so far. Also, I created a page on the wiki to list [Monitoring and Healing](https://github.com/NuGet/NuGetOperations/wiki/Monitoring-and-Healing) tasks