Refactor Oodle and Dll Prep for better Linux and macOS support

[yretenai]

This PR refactors:

• PlatformDeswizzlers: Same convention as Detex (using Constant library name instead of literal name)
• PlatformDeswizzlers.PrepareDllFile: modern dotnet APIs and early return on non-windows-64
• Detex: Use "Detex" as library name instead of "Detex.dll"
• Detex.PrepareDllFile: modern dotnet APIs and early return on non-windows-64
• Oodle: support multiple platforms and architectures.