Breaks Entity Manager in Flow 3

[Sebobo]

In the function optimizePublishedFileof the ResourcePublisherAspect class in Flow 2 the absolute path was returned and in Flow 3 only the relative path to the resource.
This breaks the optimizeFile function and leads to an Exception of the Entity Manager when doctrine tries to store a resource.
For some reason the aspect doesn't appear in the Stacktrace.

Fixed it locally by injecting resource.targets.localWebDirectoryPersistentResourcesTarget.targetOptions.path from TYPO3.Flow and using it as prefix to get the absolute path.
Not sure if that is the perfect way.

[dfeyer]

This PR fix the issue: #5

I think injecting the value is not correct, because we can have multiple target with different publishing path.

[aertmann]

PR merged thanks to @dfeyer