Added a home page prompt for missing API keys of enterprise providers (#1056)

Co-authored-by: Thorsten Sommer <SommerEngineering@users.noreply.github.com>

app/MindWork AI Studio/Tools/UserAPIKeys/PendingUserAPIKeyGroup.cs

@@ -0,0 +1,11 @@
+using AIStudio.Settings.DataModel;
+
+namespace AIStudio.Tools.UserAPIKeys;
+
+/// <summary>
+/// The providers of one configuration plugin which wait for the API key of the user. They share one key.
+/// </summary>
+/// <param name="ConfigPluginId">The ID of the configuration plugin.</param>
+/// <param name="Prompt">What the configuration plugin tells the user about obtaining the key, if anything.</param>
+/// <param name="Targets">The providers which receive the key.</param>
+public sealed record PendingUserAPIKeyGroup(Guid ConfigPluginId, DataUserAPIKeyPrompt? Prompt, IReadOnlyList<PendingUserAPIKeyTarget> Targets);