Extend configuration parsers in order to detect media files

Api/Data/EntryInterface.php

Model/BlockEntry.php

Model/Config/Parser/ContentParser.php

Model/Config/Parser/MediaDirectoryParser.php

Model/Config/Parser/MetaDataParser.php

Model/Config/Parser/Query/FetchMediaFilesFromContent.php

Model/Console/PageListCommand.php

Model/PageEntry.php

Model/Resolver/FileContentResolver.php

Model/Resolver/PathResolver.php

.../Integration/Model/Config/_files/content_provisioning.xml

Test/Integration/Model/Config/_files/result.php

...Model/Config/_files/test-files/content-with-images-1.html

...tion/Model/Config/_files/test-files/media/foobar/test.png

...egration/Model/Config/_files/test-files/media/image-1.png

.../Model/Config/_files/test-files/media/some-test-image.png

etc/content_provisioning.xsd

etc/di.xml