Add servlet filter and jersey client filter

Here's an attempt to add some convenience classes for using brave with jersey client and things that work with the servlet api.

I added the servler filter in brave-jersey just because I didn't want to create too many new modules. It should probably be in another module since it has nothing to do with jersey.

I also copied the TraceData class from brave-resteasy-spring. It also seems like something that would belong in a "common" module.

Feel free to rename, move, tear apart as you will.

PS. Tests for JerseyClientTraceFilter will be added. Jersey was just a bit annoying to unit test because of final methods.