feat: split packets definitions into separate assembly

Merge pull request #14 from Rutherther/packets-span

Rewrite packets string enumerator to use spans, add Injector for .NET 5+

feat: use ReadOnlySpan for deserialization instead of strings

Merge pull request #12 from Rutherther/packets

Implement custom packet serializer

feat: add inline packet converters generation support

feat: rewrite packet serializer generator