fix(codegen): Adds codegen for embedded objects and timer fields (#686)

* Adds code genning for embedded objects. See `AquariumState` as an example.
* Adds code genning for fields that are `Timer`. See `Aquarium` as an example.
* Codegens aquariums
* Fixes missing option for most primitive field types.

Projects/SerializationGenerator/SourceGeneration/Helpers.cs

@@ -55,5 +55,11 @@ namespace SerializationGenerator
                 "private protected"  => Accessibility.ProtectedAndInternal,
                 _                    => Accessibility.NotApplicable
             };
+
+        public static bool CanBeConstructedFrom(this ITypeSymbol? symbol, ISymbol classSymbol) =>
+            symbol is INamedTypeSymbol namedTypeSymbol && namedTypeSymbol.ConstructedFrom.Equals(
+                classSymbol,
+                SymbolEqualityComparer.Default
+            ) || symbol != null && CanBeConstructedFrom(symbol.BaseType, classSymbol);
     }
 }