Function to configure HttpConfiguration

[rossabaker]

We can bring our own HttpConfiguration, but we can't configure the one that's there. JettyBuilder should have something like:

transformJettyHttpConfiguration(f: HttpConfiguration => HttpConfiguration)

[SallyPerez]

I'm interested!

[rossabaker]

A tricky bit here is that HttpConfiguration is mutable. For this to be useful:

1. It should be HttpConfiguration => F[HttpConfiguration].
2. The jettyHttpConfiguration that's stored on the builder then needs to be an F[HttpConfiguration], so you've got something to do with the result of the above.
3. pures and flatMaps and what not until it compiles again
4. MiMa exceptions in the build