Update HttpServiceGroupConfigurer API

[rstoyanchev]

The full configure method is awkward with two separate BiConsumer's with the group repeated in each BiConsumer, only because there is no way to pass three. This creates an artificial split into into two separate callbacks for each group.

We can created dedicated callback types to use instead of the general BiConsumer, and also use the opportunity to rename the configure methods along the lines of forEachClient, forEachProxyFactory, and forEachGroup.