Third-party licenses

• convert-assets/gifenc-LICENSE.txt
• convert-assets/HEIC-NOTICES.txt
• convert-assets/libheif-LICENSE.txt
• convert-assets/pako-LICENSE.txt
• convert-assets/UTIF-LICENSE.txt
• edit-assets/inpaint/LICENSE-Apache-2.0.txt
• edit-assets/Licenses/MetadataExtractor-License.txt
• edit-assets/MODELS.md
• scan-assets/core/LICENSE
• scan-assets/exifr/LICENSE
• scan-assets/zxing/LICENSE