EZEE-3281: Variations are now returned for imageasset field type

[ViniTou]

Question	Answer
JIRA issue	EZP-3281
Type	feature/improvement
Target version	eZ Platform v3.2.0
BC breaks	no
Tests pass	yes
Doc needed	yes

It is now possible to obtain variations array for imageasset fieldtype identical to image one, i.e.
GET /api/ezp/v2/content/objects/102/versions/1

{
    "Version": {
        "_media-type": "application\/vnd.ez.api.Version+json",
        "_href": "\/api\/ezp\/v2\/content\/objects\/102\/versions\/1",
        "VersionInfo": {
            "id": 672,
            "versionNo": 1,
            "status": "PUBLISHED",
            "modificationDate": "2020-10-07T12:16:34+00:00",
            "Creator": {
                "_media-type": "application\/vnd.ez.api.User+json",
                "_href": "\/api\/ezp\/v2\/user\/users\/14"
            },
            "creationDate": "2020-10-07T12:16:19+00:00",
            "initialLanguageCode": "eng-GB",
            "languageCodes": "eng-GB",
            "VersionTranslationInfo": {
                "_media-type": "application\/vnd.ez.api.VersionTranslationInfo+json",
                "Language": [
                    {
                        "languageCode": "eng-GB"
                    }
                ]
            },
            "names": {
                "value": [
                    {
                        "_languageCode": "eng-GB",
                        "#text": "js_meme_1.png"
                    }
                ]
            },
            "Content": {
                "_media-type": "application\/vnd.ez.api.ContentInfo+json",
                "_href": "\/api\/ezp\/v2\/content\/objects\/102"
            }
        },
        "Fields": {
            "field": [
                {
                    "id": 417,
                    "fieldDefinitionIdentifier": "new_ezimageasset_1",
                    "languageCode": "eng-GB",
                    "fieldTypeIdentifier": "ezimageasset",
                    "fieldValue": {
                        "destinationContentId": "94",
                        "alternativeText": null,
                        "source": null,
                        "variations": {
                            "ezplatform_admin_ui_profile_picture_user_menu": {
                                "href": "\/api\/ezp\/v2\/content\/binary\/images\/94-399-1\/variations\/ezplatform_admin_ui_profile_picture_user_menu"
                            },
                            "gallery": {
                                "href": "\/api\/ezp\/v2\/content\/binary\/images\/94-399-1\/variations\/gallery"
                            },
                            "large": {
                                "href": "\/api\/ezp\/v2\/content\/binary\/images\/94-399-1\/variations\/large"
                            },
                            "medium": {
                                "href": "\/api\/ezp\/v2\/content\/binary\/images\/94-399-1\/variations\/medium"
                            },
                            "reference": {
                                "href": "\/api\/ezp\/v2\/content\/binary\/images\/94-399-1\/variations\/reference"
                            },
                            "small": {
                                "href": "\/api\/ezp\/v2\/content\/binary\/images\/94-399-1\/variations\/small"
                            },
                            "tiny": {
                                "href": "\/api\/ezp\/v2\/content\/binary\/images\/94-399-1\/variations\/tiny"
                            }
                        }
                    }
                }
            ]
        },
        "Relations": {
            "_media-type": "application\/vnd.ez.api.RelationList+json",
            "_href": "\/api\/ezp\/v2\/content\/objects\/102\/versions\/1\/relations",
            "Relation": [
                {
                    "_media-type": "application\/vnd.ez.api.Relation+json",
                    "_href": "\/api\/ezp\/v2\/content\/objects\/102\/versions\/1\/relations\/34",
                    "SourceContent": {
                        "_media-type": "application\/vnd.ez.api.ContentInfo+json",
                        "_href": "\/api\/ezp\/v2\/content\/objects\/102"
                    },
                    "DestinationContent": {
                        "_media-type": "application\/vnd.ez.api.ContentInfo+json",
                        "_href": "\/api\/ezp\/v2\/content\/objects\/94"
                    },
                    "SourceFieldDefinitionIdentifier": "new_ezimageasset_1",
                    "RelationType": "ASSET"
                }
            ]
        },
        "Thumbnail": {
            "_media-type": "application\/vnd.ez.api.Thumbnail+json",
            "resource": "\/bundles\/ezplatformadminui\/img\/ez-icons.svg#image",
            "width": null,
            "height": null,
            "mimeType": "image\/svg+xml"
        }
    }
}

It is also possible to fetch variations with using ezimageasset fieldId and contentId and not that related to linked image.
GET /api/ezp/v2/content/binary/images/{contentId-with-used-image-asset}-{image-asset-field-id}/variations/medium

TODO:

• Implement tests.
• Fix new code according to Coding Standards ($ composer fix-cs).
• Ask for Code Review.