Convert StomachBehavior to a component/system + rejig body namespaces (#5249)

* Convert StomachBehavior to a component/system + rejig body namespaces

* test

* slightly more namespace changes

* remove

* Hello?????

* fuck you github test runner

* reviews

* oobsy!

Content.Shared/Body/Components/SharedBloodstreamComponent.cs

@@ -0,0 +1,18 @@
+using Content.Shared.Chemistry.Components;
+using Robust.Shared.GameObjects;
+
+namespace Content.Shared.Body.Components
+{
+    public abstract class SharedBloodstreamComponent : Component
+    {
+        /// <summary>
+        ///     Attempts to transfer the provided solution to an internal solution.
+        ///     Only supports complete transfers.
+        /// </summary>
+        /// <param name="solution">The solution to be transferred.</param>
+        /// <returns>Whether or not transfer was successful.</returns>
+        public abstract bool TryTransferSolution(Solution solution);
+
+        public const string DefaultSolutionName = "bloodstream";
+    }
+}