Sonjas fixes for update of integration with DistAIX
I have fixed a few things that I noticed when updating the villasnode lib in DistAIX.
- The loopback-internal node type was missing a check of
HAS_EVENTFDto compile without this variable being true
- Path was missing a check of
WITH_HOOKSto compile without hooks enabled
- Minimum required GCC version is 8 and clang version is 7 due to dependency on filesystem library in config and config_helper; cmake checks this now and will report a failure if the compiler is too old, eventually, other compilers should be included in this check if needed.
- Missing include of super_node.hpp in mqtt node type
- I fixed the rabbitmq version in the gitlab CI to 3.8 since there are breaking changes for the config in version 3.9