[RandyCupic]

Replaces #122, rebased onto 4.0 (the branch was renamed from 3.0-multiupload to multiupload, which closed #122).

Adds a collection mode to the remote media form type and picker. Editors can select or upload several resources, reorder them, and edit alt text, caption and crops per item. Single-media fields behave as before.

• RemoteMediaType is split into a single type and a new RemoteMediaCollectionType. The submitted collection replaces the stored one, so clearing a gallery sticks.
• Malformed payloads fail the form instead of emptying the collection. Location ids that don't belong to the edited value are ignored.
• Picker:
  • multi-select and drag to reorder;
  • optional upload limit per field;
  • items already in the gallery are skipped when browsing or uploading;
  • folder placeholders never create folders in Cloudinary.
• Replacing a single image keeps its watermark.
• The bundled CKEditor plugin passes the new picker options, so embeds keep working with the shared picker.
• Translation keys for the multi-select UI (en, hr, no) and a new Norwegian Bokmål (nb) file.
• Dist assets in bundle/Resources/public rebuilt (Node 12).

Behaviour changes:

• If a resource no longer exists in Cloudinary when its metadata is saved, the local resource and its locations are kept and a warning with the remote id is logged. Before, the resource was deleted locally, which also removed it from every other field using it.
• Tags are compared and stored sorted, so a different tag order no longer triggers a Cloudinary update on every save.

CI: the test matrix now uses Symfony ~6.4.0 instead of ~6.2.0. Composer refuses every 6.2 release because of security advisories, so that job could not install dependencies; it fails the same way on 3.0 since February. 6.4 is the maintained LTS.

Rebase notes:

• The merge of origin/3.0 was dropped by the rebase; its test expectation change in UploadTest is restored in a separate commit.
• The folder-aware existing resource error from Feature/asset folder public id prefix #123 is ported to MultiUploadInline.vue (UploadModal.vue is removed here), with the nb translation and the rebuilt app bundle.
• The CI change to Symfony ~6.4.0 is already in 4.0, so that commit was skipped.

[RandyCupic]

@mivancic Why only these two were moved to translations?

[RandyCupic]

@mivancic You decided to keep both single and collection? Hmm, is this to support v3.0?

[RandyCupic]

@mivancic When you select multiple images in gallery, and then you go to select more, it doesn't show these that are already added as selected or grayed out. In fact, you can select them again. It won't add them again but it messes up with limitation. For example, I've put limit to 5 and I've selected 3 images. Then I went to select more, and again I've selected 2 of the same images so I was not able to select more (as I already had 5 images in total) but when you actually go to add them, there are only 3.