SM-2327: Refactor camel-cxf-rest example code (closes #14)

- Use Map instead of List for storing person instances
- Follow REST principles by using appropriate HTTP response codes and
response messages
- Follow JAX-RS programming model by returning Response instance where
appropriate
- Remove unneeded fields and annotations

Signed-off-by: Gregor Zurowski <gregor@zurowski.org>

(Cherry picked from the commit c4dd2af3b1d59e1fb9a00587810390d3096f8b5b)