Docker ssl

I encountered difficult problems with the self-signed certificates available in master when used inside composed docker containers. Either the pkm was not accessible, or frama-c was not able to call back the pkm. Or my tools were not able to access the pkm from their own containers. This merge request replaces the two certificates frama-c.crt and pkm.crt by a unique pkm_docker.crt which allows the validation of several hostnames, including those generated by docker-compose with the updated configuration and those put in the local /etc/hosts. A script is given to allow users to produce their own certificate with the same characteristics.