Changed drinks to use ECS (#4948)

Co-authored-by: Paul Ritter <ritter.paul1@googlemail.com>
Co-authored-by: metalgearsloth <31366439+metalgearsloth@users.noreply.github.com>
Co-authored-by: metalgearsloth <comedian_vs_clown@hotmail.com>

Content.Server/Chemistry/EntitySystems/SolutionContainerSystem.Capabilities.cs

@@ -109,6 +109,14 @@ namespace Content.Server.Chemistry.EntitySystems
             return solution.CurrentVolume;
         }
 
+        public ReagentUnit DrainAvailable(EntityUid uid)
+        {
+            if (!TryGetDrainableSolution(uid, out var solution))
+                return ReagentUnit.Zero;
+
+            return solution.CurrentVolume;
+        }
+
         public bool HasFitsInDispenser(IEntity owner)
         {
             return !owner.Deleted && owner.HasComponent<FitsInDispenserComponent>();