Retrieve the `qmstr` binary

[marcomicera]

At the moment, two out of three builders need the qmstr binary to send build information to the Quartermaster master/orchestrator.

The Python and CMake builder use it (qmstr run ...).
The Maven builder does this by patching the root pom.xml file, injecting the Quartermaster Maven plugin, so it won't need it.

[marcomicera]

• The Docker image entrypoint should still be the synchronization main.go file: the builder still needs to connect to RabbitMQ and wait for the order from the Orchestrator
• The callback function (that is invoked as soon as the builder receives the order from the Orchestrator) needs to build the project (e.g., python3 setup.py qmstr for Python, qmstr run cmake ... for C, and mvn package ... for Java)
  • We will include the qmstr binary in this repository to be able to compile C and Python projects. Upon creating the Maven builder, we will revert this.
  • We need to be able to run CLI commands from Golang