Configure Jackson using class annotations.

src/main/java/org/torproject/onionoo/docs/Document.java

src/main/java/org/torproject/onionoo/docs/DocumentStore.java

...n/java/org/torproject/onionoo/server/ResponseBuilder.java

...va/org/torproject/onionoo/server/ResourceServletTest.java

...g/torproject/onionoo/writer/GraphHistoryCompilerTest.java