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.

src/hindsightgrpc/topology.h

@@ -66,7 +66,7 @@ namespace hindsightgrpc {
   /* An API provided by the service */
   class API {
     public:
-      API(std::string name, int exec, std::vector<Outcall> children) : name(name), exec(exec), children(children) {}
+      API(std::string name, double exec, std::vector<Outcall> children) : name(name), exec(exec), children(children) {}
       API() {}
       friend std::ostream& operator<<(std::ostream& os, const API& api) {
         os << api.name << ": " << api.exec << "\n";
@@ -79,7 +79,7 @@ namespace hindsightgrpc {
       std::vector<Outcall> children;
       
       std::string name;
-      int exec;
+      double exec;
   };
 
   /* A service config*/