Fixed EZP-20687: Existing file path outside the current vardir throws an exception

*WORK IN PROGRESS*

Only Image is affected, since BinaryFile and Media both store the filename, and rebuild the path dynamically.

The fix catches the IO exception in ImageStorage, and logs an error.

Tasks:
- [x] Catch the IOService exception, and log an error in ImageStorage
- [ ] Consider using a dedicated exception in order to make this Legacy only
- [ ] Enhance the test
- [ ] Try to make the image "usable" in read mode
- [ ] See what was supported in Legacy when an image had such a path, and update accordingly