[Milestone] AssemblyLoader completed.

Details:
- Assembly Mgmt Service for loading now a separate interface, not intended for normal use.
- Assembly Loader work; implemented custom dictionary key and table.
- Assembly loading work.
- EventService completed.
- Moved assembly extensions to ModUtils.cs
- Work to event service.
NetworkService work
- Added ImpromptuInterfaces package.
- Networking Service work to support NetVars
- Event Service
- Added assemblies references package for script compilation. Updated Roslyn version for compatibility.
- Package Loading work.
Swap Harmony to HarmonyX
- More refactor conversion to FluentResults.
- Updated StylesService to return Results.
- Refactor of PackageService partially complete.
- Made IService.Reset() required to return a Result.
- Moved plugin/assembly related code to their own folder (same namespace).
- Updated interfaces to reflect the use of Result<T>.
- Partial refactor, incomplete.
- Added 'FluentResults' so we can stop using cursed Exception-based flow control in loading code.
- Added 'OneOf' nuget package: https://github.com/mcintyre321/OneOf
for the implementation of the Optional<T> pattern and complex discrete return types instead of cursed enums (see current AssemblyManager.cs).
- Reapplied old branch changes.

Barotrauma/BarotraumaShared/SharedSource/LuaCs/Networking/NetInterfaceCompat.cs

@@ -11,7 +11,7 @@ namespace Barotrauma.LuaCs.Networking;
 public interface INetWriteMessage
 {
     internal IWriteMessage Message { get; }
-    internal void SetMessage(IWriteMessage msg);
+    internal INetWriteMessage SetMessage(IWriteMessage msg);
 
     void WriteBoolean(bool val) => Message.WriteBoolean(val);
 
@@ -84,7 +84,7 @@ public interface INetWriteMessage
 public interface INetReadMessage
 {
     internal IReadMessage Message { get; }
-    internal void SetMessage(IReadMessage msg);
+    internal INetReadMessage SetMessage(IReadMessage msg);
 
     bool ReadBoolean() => Message.ReadBoolean();
     void ReadPadBits() => Message.ReadPadBits();
@@ -131,20 +131,30 @@ public class NetWriteMessage : INetWriteMessage
 
     IWriteMessage INetWriteMessage.Message => Message;
 
-    void INetWriteMessage.SetMessage(IWriteMessage msg)
+    INetWriteMessage INetWriteMessage.SetMessage(IWriteMessage msg)
     {
         Message = msg;
+        return this;
     }
 }
 
+internal static class NetHelperExtensions
+{
+    internal static INetWriteMessage ToNetWriteMessage(this IWriteMessage msg) =>
+        ((INetWriteMessage)new NetWriteMessage()).SetMessage(msg);
+    internal static INetReadMessage ToNetReadMessage(this IReadMessage msg) =>
+        ((INetReadMessage)new NetReadMessage()).SetMessage(msg);
+}
+
 public class NetReadMessage : INetReadMessage
 {
     private IReadMessage Message { get; set; }
     IReadMessage INetReadMessage.Message => Message;
 
-    void INetReadMessage.SetMessage(IReadMessage msg)
+    INetReadMessage INetReadMessage.SetMessage(IReadMessage msg)
     {
         Message = msg;
+        return this;
     }
 }