Add CDI support to HTTP (and other) classes

[acoburn]

CDI offers a standard J2EE-based dependency injection framework that could greatly simplify object creation in Trellis.

[ajs6f]

👍 x 17.

[acoburn]

(Note to self) A big part of this issue will involve removing the ability to pass null values into various constructors. Instead, a "null component" such as the NoopEventService should be used in those cases. This will allow for JSR 330 Inject annotations to be more easily used.

For example, the EventService parameter in the TriplestoreResourceService will need to become required instead of being wrapped in an Optional.