Add super basic group model/command

PluralKit.Core/Models/Patch/GroupPatch.cs

@@ -0,0 +1,13 @@
+#nullable enable
+namespace PluralKit.Core
+{
+    public class GroupPatch: PatchObject
+    {
+        public Partial<string> Name { get; set; }
+        public Partial<string?> Description { get; set; }
+
+        public override UpdateQueryBuilder Apply(UpdateQueryBuilder b) => b
+            .With("name", Name)
+            .With("description", Description);
+    }
+}