Use tags and service name to derive a process ID in the jaeger REST API

[fmassot]

We added in #4197 Jaeger REST endpoints.

The code logic used to convert gRPC objects into the REST ones has a missing part. During the conversion, we build process IDs from the service name, we should also take into account tags to build those IDs, ref

[Warfields]

Should this be closed by @ph 's commit?