Enable head-based sampling and add some scripts for large scale deployment

This PR is related to the following issues:

• Head based sampling: https://gitlab.mpi-sws.org/cld/tracing/hindsight-grpc/-/issues/17
• Data type of duration: https://gitlab.mpi-sws.org/cld/tracing/hindsight-grpc/-/issues/20
• Docker images and scripts for deployment: https://gitlab.mpi-sws.org/cld/tracing/hindsight-grpc/-/issues/15

Side note, gen_address.py and config/alibaba_parse.py are not used, will be discarded later.

docker/DockerfileHindsightCollector

@@ -11,4 +11,6 @@ RUN cd agent &&\
     mv main /hindsight_collector
 
 # Todo: more configuration
-ENTRYPOINT ["/hindsight_collector"]
\ No newline at end of file
+ENTRYPOINT ["/hindsight_collector", "-out", "hindsight_traces"]
+# to access the generated traces: 
+#   -v ${PWD}/hindsight_traces:/root/hindsight/hindsight_traces
\ No newline at end of file