Build scdaq RPM in CI

We now build the scdaq RPM in the CI. The docker image is based on the cern/cc7-base image with additional packages to build it. (The dockerfile is at https://gitlab.cern.ch/scouting-demonstrator/scouting-docker-images/-/blob/main/dockerfile-scdaq-builder.)

One curiosity is that I needed to add -pthread to the Makefile, which I don't fully understand. (Maybe @meschi or @pzejdl have an idea?)

src/Makefile

@@ -27,7 +27,7 @@ CXXFLAGS = -std=c++11 -Wall -Wextra -O0 -g -rdynamic
 #CXXFLAGS = -std=c++11 -Wall -Wextra -g -rdynamic
 
 CFLAGS = $(CXXFLAGS)
-LDFLAGS = -ltbb -ltbbmalloc -lboost_thread -lcurl
+LDFLAGS = -ltbb -ltbbmalloc -lboost_thread -lcurl -pthread
 
 CPPFLAGS = -I. -Iwzdma