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/LungComponent.cs

@@ -8,7 +8,7 @@ namespace Content.Server.Body.Components;
 [RegisterComponent, Access(typeof(LungSystem))]
 public sealed partial class LungComponent : Component
 {
-    [DataField("air")]
+    [DataField]
     [Access(typeof(LungSystem), Other = AccessPermissions.ReadExecute)] // FIXME Friends
     public GasMixture Air { get; set; } = new()
     {
@@ -16,7 +16,15 @@ public sealed partial class LungComponent : Component
         Temperature = Atmospherics.NormalBodyTemperature
     };
 
-    [ViewVariables]
-    [Access(typeof(LungSystem), Other = AccessPermissions.ReadExecute)] // FIXME Friends
-    public Solution LungSolution = default!;
+    /// <summary>
+    /// The name/key of the solution on this entity which these lungs act on.
+    /// </summary>
+    [DataField]
+    public string SolutionName = LungSystem.LungSolutionName;
+
+    /// <summary>
+    /// The solution on this entity that these lungs act on.
+    /// </summary>
+    [DataField]
+    public Entity<SolutionComponent>? Solution = null;
 }