rvi_common:get_static_node(Service) should return best-matching result

[magnusfeuer]

When a serivce is matched against static nodes in rvi_common:get_static_node(Service),
the service should be prefix matched against all available static nodes, returning the static node with the longest prefix match against the provided service.

This allows for a static node to be configured for jlr.com/backend/sota that only handles software over the air, while another node can be configured for jlr.com/backend to handle all other types of requests.