UI: Pretty Atmosphère mod names (#601)

Changes the mods from the Atmosphère folder to show a pretty name
instead of just the name of the folder they're in, because those names
are always just a title ID.

NOTE: The DLC names are from the file names, not retrieved from the
content file itself like the main applications.

src/Ryujinx/Utilities/AppLibrary/ApplicationLibrary.cs

@@ -111,6 +111,30 @@ namespace Ryujinx.Ava.Utilities.AppLibrary
             return data;
         }
 
+        /// <summary>
+        ///     Gets a name for an available content file based on the Application ID '<paramref name="id"/>'.
+        ///     <br/><br/>
+        ///     For Applications, this returns the localized name of the app found in the file.
+        ///     For DLCs, this returns the name of the file that contains the DLC, minus the file extension.
+        /// </summary>
+        /// <param name="id">The Application ID to search for.</param>
+        /// <remarks>
+        /// If the provided Application ID does not have a corresponding Application OR DLC file,
+        /// <paramref name="id"/> formatted as hexadecimal is returned.
+        /// </remarks>
+        /// <returns>A formatted Application name, or <paramref name="id"/> as hexadecimal if none is found.</returns>
+        public string GetNameForApplicationId(ulong id)
+        {
+            DynamicData.Kernel.Optional<ApplicationData> appData = Applications.Lookup(id);
+            if (appData.HasValue)
+                return appData.Value.Name;
+            
+            if (DownloadableContents.Keys.FindFirst(x => x.TitleId == id).TryGet(out DownloadableContentModel dlcData))
+                return dlcData.FileName;
+
+            return id.ToString("X16");
+        }
+
         /// <exception cref="LibHac.Common.Keys.MissingKeyException">The configured key set is missing a key.</exception>
         /// <exception cref="InvalidDataException">The NCA header could not be decrypted.</exception>
         /// <exception cref="NotSupportedException">The NCA version is not supported.</exception>