Consider allowing query strings in health probes

[robbieknuth]

What should we add or change to make your life better?

Health probes are currently implemented strictly as paths. It is not possible to probe at at /myhealth?key=value. The resulting probe becomes /myhealth%3Fkey=value

It may or may not be desirable to include query strings in DefaultProbingRequestFactory, however I am opening this for consideration.

Why is this important to you?

Our current health probe includes a query string. It is simple enough to work around this by implementing a IProbingRequestFactory.