New test for EZP-23288: Allow to set modifier of Content Versions & ContentType
Fix EZP-23287: Empty Image FieldType triggers twig_error_runtime

check if image is set, otherwise don't try to render the image

(cherry picked from commit 93db5acadfc4cdc81cdb284bad0f4d97bda4596b)
Fix EZP-23287: Output img tag for alt text on invalid image alias

Yes, it is a thing: http://stackoverflow.com/questions/5775469/whats-the-valid-way-to-include-an-image-with-no-src
Merge pull request #990 from ezsystems/fix_EZP-23287_emptyImage

Fix EZP-23287: empty Image FieldType triggers twig_error_runtime
EZP-23437: IO interfaces split + flysystem specs
EZP-23492: Add dumpAssetsHelpText for use with composer update
DFS: Fixed wrong scope in stream file listener

Request listeners are all initialized at the same time, and the siteaccess listener is one of them.
This means that we can't rely on dynamic parameters, and must use the ConfigResolver directly
to get the io url_prefix.

Furthermore, the image legacy io service has to be made lazy, or else the prefixes it uses will be
reset before the ConfigResolver is configured.
Merge pull request #1041 from ezsystems/dfs_stream_listener_prefix_scope

DFS: Fixed wrong scope in stream file listener
Fix EZP-23495: Catch correct exception
EZP-23329: hint read-only property
EZP-23329: remove exception from method that needs no implementation
EZP-23329: implement Indexable for ezinteger FieldType
EZP-23329: specify value type for ContentTypeGroupId criterion
EZP-23329: first implementation of Elasticsearch storage
Fix EZP-23486: don't fallback to legacy on front-end preview
Merge pull request #953 from ezsystems/impl-EZP-22564-elasticsearch-storage

EZP-23329: Implement search SPI on Elasticsearch
EZP-23492: Add dumpAssets question to specify other env variable
Merge pull request #1043 from wizhippo/ezimage-exception-fix

Fix EZP-23495: Catch correct exception
Merge pull request #1040 from ezsystems/dx_dump_asset

[DX] Improve assetic dump use with composer
Fixed typo