feat: use ReadOnlySpan for deserialization instead of strings

Merge pull request #16 from Rutherther/packets-list-inline-serializer

Add generation of packet list inline serializer

feat: accept types and variable names in inline converter generators instead of packet parameters

feat: add extensions for checking type nullability

Merge pull request #12 from Rutherther/packets

Implement custom packet serializer

feat: add inline packet converters generation support

feat: add support for conditional packet attribute

fix: correct generated syntax errors

feat: rewrite packet serializer generator

feat: add source generator for basic packet converter