Too many refactors in one:

- Allowed adding ephemeral(ish) views and functions
- Moved message_count to a concrete database field
- Moved most proxy logic to a stored procedure
- Moved database files around and refactored schema manager

PluralKit.Core/Modules.cs

@@ -25,7 +25,7 @@ namespace PluralKit.Core
             builder.RegisterType<DbConnectionCountHolder>().SingleInstance();
             builder.RegisterType<DbConnectionFactory>().AsSelf().SingleInstance();
             builder.RegisterType<PostgresDataStore>().AsSelf().As<IDataStore>();
-            builder.RegisterType<SchemaService>().AsSelf();
+            builder.RegisterType<Schemas>().AsSelf();
             
             builder.Populate(new ServiceCollection().AddMemoryCache());
             builder.RegisterType<ProxyCache>().AsSelf().SingleInstance();