Apply a watermark

curl --request POST \
  --url https://convertly.sh/api/media/watermark \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: multipart/form-data' \
  --form file='@example-file' \
  --form 'sourceUrl=<string>' \
  --form async=false \
  --form 'text=<string>' \
  --form watermarkFile='@example-file' \
  --form position=bottom-right \
  --form opacity=0.72 \
  --form margin=32 \
  --form watermarkWidth=123

{
  "files": [
    {
      "filename": "<string>",
      "mimeType": "<string>",
      "originalSize": 123,
      "finalSize": 123,
      "downloadUrl": "<string>"
    }
  ]
}