Simplify/Clean code and try to make it better

* all method helper to be clear on what we expose about config of the job
* Remove Job::getConfig
* by removing class ProcessorFactory
* Remove useless getter ExecutionContext::getLogger
* create JobConfig::resolveExecOptions
* remove useless getter
* TypeHinting on ETLProcessors classes

We no longer have an implementation for JobProcessor except the ETL one. No big deal for now.
complete tests