fix(codegen): Creates multiple steps for serialization source generator (#628)

Roslyn Source generators are not supposed to access I/O. To get around this we have to use `AdditionalFiles` to give the analyzer access to read/load the schema files.
To write the schema files we have to use a separate program altogether.

- [X] Adds SerializationSchemaGenerator
- [X] Splits out the SerializationGenerator code

Projects/SerializationGenerator/SerializableMigration/Rules/ArrayMigrationRule.cs

@@ -18,7 +18,7 @@ using System.Collections.Immutable;
 using System.Text;
 using Microsoft.CodeAnalysis;
 
-namespace SerializationGenerator
+namespace SerializableMigration
 {
     public class ArrayMigrationRule : ISerializableMigrationRule
     {

Projects/SerializationGenerator/SerializableMigration/Rules/EnumMigrationRule.cs

@@ -17,8 +17,9 @@ using System;
 using System.Collections.Immutable;
 using System.Text;
 using Microsoft.CodeAnalysis;
+using SourceGeneration;
 
-namespace SerializationGenerator
+namespace SerializableMigration
 {
     public class EnumMigrationRule : ISerializableMigrationRule
     {

Projects/SerializationGenerator/SerializableMigration/Rules/HashSetMigrationRule.cs

@@ -17,8 +17,9 @@ using System;
 using System.Collections.Immutable;
 using System.Text;
 using Microsoft.CodeAnalysis;
+using SourceGeneration;
 
-namespace SerializationGenerator
+namespace SerializableMigration
 {
     public class HashSetMigrationRule : ISerializableMigrationRule
     {

Projects/SerializationGenerator/SerializableMigration/Rules/KeyValuePairMigrationRule.cs

@@ -17,8 +17,9 @@ using System;
 using System.Collections.Immutable;
 using System.Text;
 using Microsoft.CodeAnalysis;
+using SourceGeneration;
 
-namespace SerializationGenerator
+namespace SerializableMigration
 {
     public class KeyValuePairMigrationRule : ISerializableMigrationRule
     {
@@ -124,7 +125,7 @@ namespace SerializationGenerator
             );
 
             source.AppendLine(
-                $"{indent}{property.Name} = new {SerializableEntityGeneration.KEYVALUEPAIR_STRUCT}<{keyType}, {valueType}>(key, value);"
+                $"{indent}{property.Name} = new {SymbolMetadata.KEYVALUEPAIR_STRUCT}<{keyType}, {valueType}>(key, value);"
             );
         }
 

Projects/SerializationGenerator/SerializableMigration/Rules/ListMigrationRule.cs

@@ -17,8 +17,9 @@ using System;
 using System.Collections.Immutable;
 using System.Text;
 using Microsoft.CodeAnalysis;
+using SourceGeneration;
 
-namespace SerializationGenerator
+namespace SerializableMigration
 {
     public class ListMigrationRule : ISerializableMigrationRule
     {

Projects/SerializationGenerator/SerializableMigration/Rules/PrimitiveTypeMigrationRule.cs

@@ -18,8 +18,9 @@ using System.Collections.Immutable;
 using System.Linq;
 using System.Text;
 using Microsoft.CodeAnalysis;
+using SourceGeneration;
 
-namespace SerializationGenerator
+namespace SerializableMigration
 {
     public class PrimitiveTypeMigrationRule : ISerializableMigrationRule
     {
@@ -89,7 +90,7 @@ namespace SerializationGenerator
             var propertyName = property.Name;
             var argument = property.RuleArguments.Length >= 1 ? property.RuleArguments[0] : null;
 
-            const string ipAddress = SerializableEntityGeneration.IPADDRESS_CLASS;
+            const string ipAddress = SymbolMetadata.IPADDRESS_CLASS;
             const string date = "System.DateTime";
 
             var readMethod = property.Type switch

Projects/SerializationGenerator/SerializableMigration/Rules/PrimitiveUOTypeMigrationRule.cs

@@ -17,8 +17,9 @@ using System;
 using System.Collections.Immutable;
 using System.Text;
 using Microsoft.CodeAnalysis;
+using SourceGeneration;
 
-namespace SerializationGenerator
+namespace SerializableMigration
 {
     public class PrimitiveUOTypeMigrationRule : ISerializableMigrationRule
     {

Projects/SerializationGenerator/SerializableMigration/Rules/SerializableInterfaceMigrationRule.cs

@@ -17,8 +17,9 @@ using System;
 using System.Collections.Immutable;
 using System.Text;
 using Microsoft.CodeAnalysis;
+using SourceGeneration;
 
-namespace SerializationGenerator
+namespace SerializableMigration
 {
     public class SerializableInterfaceMigrationRule : ISerializableMigrationRule
     {

Projects/SerializationGenerator/SerializableMigration/Rules/SerializationMethodSignatureMigrationRule.cs

@@ -17,8 +17,9 @@ using System;
 using System.Collections.Immutable;
 using System.Text;
 using Microsoft.CodeAnalysis;
+using SourceGeneration;
 
-namespace SerializationGenerator
+namespace SerializableMigration
 {
     public class SerializationMethodSignatureMigrationRule : ISerializableMigrationRule
     {