Update LoggerAwareInterface.php

Added accessor for logger instance. Doc blocks.
Update LoggerAwareTrait.php

Added accessor
Update LoggerAwareInterface.php

The accessor being defined in the interface would break current implementations of the interface. Nevertheless, for consistency, I would like to see this somewhen active as it is implemented with the LoggerAwareTrait.
Update LoggerAwareInterface.php

trailing spaces removed
Update LoggerAwareTrait.php

removed trailing spaces
Update LoggerAwareInterface.php
Merge pull request #4742 from sarge-ch/Logger

LoggerAwareInterface and its Trait
Merge branch 'feature/4742' into develop

Close #4742