Apel joiner

This branch :
- creates a defined resource, which can be used to define multiple apel joiners on one host : this is usefull for managing several separate apel databases in one single place.
- adds ruby template parameters wherever needed
- separates several things such as mysql configuration, ssm::sender into their own class.
- attempts to keep original behaviour. The only changed behavious is the default broker configuration and queues
- allows for NOT installing the EGI CAs and EMI repos (if already done outside the module)