Added TolerantIOService and MissingBinaryFile

See spec. TolerantIOService overlays IOService, and tolerates
files that are returned as missing by handlers, returning
fake MissingBinaryFile objects when applicable.

EZP-23534
Removed logger from binary storage handlers

No longer needed, since the TolerantIOService will take care of
logging, and will fake missing files.

EZP-23534
Tested TolerantIOService

- in SPI integration tests (all binary ones)
- unit tests

EZP-23534
EZP-23534: Log error if source image doesn't exist

Closes #1060, #1020
EZP-23534: Catching NotResolvableException
EZP-23534: Added new tests for AliasGenerator
EZP-23534: Moved SourceImageNotFoundException to eZ\Publish\Core\MVC\Exception
EZP-23534: Adapt AliasGenerator underlying services (BinaryLoader and IORepositoryResolver)

Ensure that appropriate exceptions are thrown when:

* Binary files returned by IOService are invalid (`MissingBinaryFile`).
* NotFound exceptions are caught.
EZP-23534: bc + unit test + spec title
Merge pull request #1058 from ezsystems/EZP-23534-tolerant_io_service

Implemented tolerant IO Service
EZP-23534: Fixed SourceImageNotFoundException not caught in Twig ContentExtension
Merge branch 'upstream'