Seal/abstract/virtual everything (#6739)

Content.Server/Armor/ArmorComponent.cs

@@ -5,7 +5,7 @@ using Robust.Shared.Serialization.Manager.Attributes;
 namespace Content.Server.Armor
 {
     [RegisterComponent]
-    public class ArmorComponent : Component
+    public sealed class ArmorComponent : Component
     {
         [DataField("modifiers", required: true)]
         public DamageModifierSet Modifiers = default!;

Content.Server/Armor/ArmorSystem.cs

@@ -3,7 +3,7 @@ using Robust.Shared.GameObjects;
 
 namespace Content.Server.Armor
 {
-    public class ArmorSystem : EntitySystem
+    public sealed class ArmorSystem : EntitySystem
     {
         public override void Initialize()
         {