Solution Entities (#21916)

* Creates Content.Shared.Chemistry.Solutions
Copies Solution class to new namespace
Obsoletes old Solution class

* Switches over to the Solutions.Solution Solution

* Creates Content.Shared.Chemistry.Containers
Copies relevant components/systems to the new namespace
Obsoletes old versions

* Switches over to the Containers.XYZ namespace

* Creates SolutionSystem and obsoletes old SolutionContainerSystem methods

* Start using SolutionSystem for Solution manipulation

* EnumerateSolutions

* Move TryGetMixableSolution

* Move EnsureSolution to Server

* Create Solution Entities

* Stop using obsolete solution system methods

* Fix prototype component tests

* Add using ..Audio.Systems; back

* Wrap solution container slots in ContainerSlots

* Actually add the slot to the solution container map

* Dirty SolutionContainerComponent when ensuring solutions

* Revert namespace changes

* Remerge SolutionSystem and SolutionContainerSystem

* SolutionContainerManagerComponent refactor

* Avoid wrapping necessary code in DebugTools.Assert as it is removed when compiling for release

* Readd examine reagent sorting

* Fix errors

* Poke tests

* Fix solution names not being applied

* Fix WoolyComponent including statement

* Fix merge skew

* Fix compile errors

* Make reactions use solntities

* Reindent solution class namespace

* Field attribute changes

* AutoGenerateComponentState for SolutionContainerComponent

* SolutionContainerComponent -> ContainedSolutionComponent

* ref ReactionAttemptEvent

* Denetwork preinit solutions

* Misc 1

* Nullable TryGetSolution out vars

* Cache associated solutions

* Fix merge skew

* Use explicit regions in SharedSolutionContainerSystem.Capabilities

* Add debug assert

* Use explicit regions in SharedSolutionContainerSystem.Relay + ref SolutionContainerChangedEvent

* ContainedSolutionComponent.Name -> ContainedSolutionComponent.ContainerName

* SolutionComponent doc comments

* Implicit DataField names and property purge

* ReagentEffect DataField names

* Local variables for readability

* Sort using statements + Entity<T> event handlers

* Fix compile erros

* Fix compile errors

---------

Co-authored-by: ElectroJr <leonsfriedrich@gmail.com>

Content.Server/Body/Components/StomachComponent.cs

@@ -2,7 +2,6 @@
 using Content.Server.Nutrition.EntitySystems;
 using Content.Shared.Chemistry.Components;
 using Content.Shared.Chemistry.Reagent;
-using Content.Shared.FixedPoint;
 using Content.Shared.Whitelist;
 
 namespace Content.Server.Body.Components
@@ -15,26 +14,32 @@ namespace Content.Server.Body.Components
         /// <summary>
         ///     How fast should this component update, in seconds?
         /// </summary>
-        [DataField("updateInterval")]
+        [DataField]
         public float UpdateInterval = 1.0f;
 
+        /// <summary>
+        ///     The solution inside of this stomach this transfers reagents to the body.
+        /// </summary>
+        [DataField]
+        public Entity<SolutionComponent>? Solution = null;
+
         /// <summary>
         ///     What solution should this stomach push reagents into, on the body?
         /// </summary>
-        [DataField("bodySolutionName")]
+        [DataField]
         public string BodySolutionName = BloodstreamComponent.DefaultChemicalsSolutionName;
 
         /// <summary>
         ///     Time in seconds between reagents being ingested and them being
         ///     transferred to <see cref="BloodstreamComponent"/>
         /// </summary>
-        [DataField("digestionDelay")]
+        [DataField]
         public float DigestionDelay = 20;
 
         /// <summary>
         ///     A whitelist for what special-digestible-required foods this stomach is capable of eating.
         /// </summary>
-        [DataField("specialDigestible")]
+        [DataField]
         public EntityWhitelist? SpecialDigestible = null;
 
         /// <summary>