Fix thumbnail issues

[geourjoa]

• [ ] When we upload media, we must generate thumbnail on the upload
• [ ] When we link external media, we must generate thumbnail and create associated folder on the filesystem
• [ ] When create Manifest
  • [ ] Add field thumbnail URL for the manifest
  • [ ] If the URL come from Arvest backend, add the _thumbnail suffix
  • [ ] Else use the given URL and trigger warning if media is more than XSize (Xsize is in .env)
  • [ ] Add preview aside to thumbnail field
  • [ ] Media side panel
    • [ ] The medias displayed are not the true media but the preview
    • [ ] Add possibilty to upload media directly from the side panel
    • [ ] Add possibilité to link media directly from the side panel
  • [ ] When edit project, add the possibility to add thumbail. You must use right panel to to that

[geourjoa]

TODO