Fix thermoregulation + rebalance/refactor FlammableComponent (#5406)

Co-authored-by: Paul Ritter <ritter.paul1@googlemail.com>
Co-authored-by: Tomeno <tomeno@lulzsec.co.uk>

Content.Server/Atmos/Components/FlammableComponent.cs

@@ -31,5 +31,9 @@ namespace Content.Server.Atmos.Components
         [ViewVariables(VVAccess.ReadWrite)]
         [DataField("canResistFire")]
         public bool CanResistFire { get; private set; } = false;
+
+        [DataField("damage", required: true)]
+        [ViewVariables(VVAccess.ReadWrite)]
+        public DamageSpecifier Damage = default!;
     }
 }