Fix IINA is not associated with GIF files, #3679 (#3680)

* Fix IINA is not associated with GIF files, #3679

The commit in the pull request will:
- Add a document type entry for GIF files to Info.plist
- Add document icons for GIF files as Assets

* Fix IINA is not associated with GIF files, #3679

The commit in the pull request will:
- Add an imported type entry for GIF files to Info.plist
- Add a document type entry for GIF files to Info.plist
- Add document icons for GIF files as Assets

Thank you @Zabriskije for creating the document icon.

Co-authored-by: Zabriskije <zabriskije@gmail.com>

---------

Co-authored-by: Zabriskije <zabriskije@gmail.com>

iina/Assets.xcassets/DocIcons/Contents.json

@@ -1,6 +1,6 @@
 {
   "info" : {
-    "version" : 1,
-    "author" : "xcode"
+    "author" : "xcode",
+    "version" : 1
   }
-}
+}

iina/Info.plist

@@ -145,6 +145,26 @@
 			<key>NSPersistentStoreTypeKey</key>
 			<string>XML</string>
 		</dict>
+		<dict>
+			<key>CFBundleTypeExtensions</key>
+			<array>
+				<string>gif</string>
+			</array>
+			<key>CFBundleTypeIconFile</key>
+			<string>doc_gif.icns</string>
+			<key>CFBundleTypeIconSystemGenerated</key>
+			<integer>0</integer>
+			<key>CFBundleTypeName</key>
+			<string>GIF image</string>
+			<key>CFBundleTypeRole</key>
+			<string>Viewer</string>
+			<key>LSHandlerRank</key>
+			<string>Default</string>
+			<key>LSTypeIsPackage</key>
+			<false/>
+			<key>NSPersistentStoreTypeKey</key>
+			<string>XML</string>
+		</dict>
 		<dict>
 			<key>CFBundleTypeExtensions</key>
 			<array>
@@ -1338,6 +1358,31 @@ Released under GPLv3.</string>
 				</array>
 			</dict>
 		</dict>
+		<dict>
+			<key>UTTypeConformsTo</key>
+			<array>
+				<string>com.compuserve.gif</string>
+			</array>
+			<key>UTTypeDescription</key>
+			<string>GIF image</string>
+			<key>UTTypeIconFile</key>
+			<string>doc_gif</string>
+			<key>UTTypeIcons</key>
+			<dict/>
+			<key>UTTypeIdentifier</key>
+			<string>io.iina.gif</string>
+			<key>UTTypeTagSpecification</key>
+			<dict>
+				<key>public.filename-extension</key>
+				<array>
+					<string>gif</string>
+				</array>
+				<key>public.mime-type</key>
+				<array>
+					<string>image/gif</string>
+				</array>
+			</dict>
+		</dict>
 	</array>
 </dict>
 </plist>