Bolt in the Jackson Guava support for handling Optional<T> types properly.

This dragged in dropwizard-core as a dependency.
Debug log inbound annotations.
Remove JsonSnakeCase so we don't have to depend on it in telemetry-lib for the Span class.
Add some dependency exclusions for things that aren't strictly needed, which will cause shading problems in telemetry-agent later on.
Preserve the content type of the proxied content.