refactor: split string converters

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

Add generation of packet list inline serializer

feat: use StringBuilder Append overloads

Merge pull request #12 from Rutherther/packets

Implement custom packet serializer

fix: support +10 upgrade in UpgradeRareSubPacket

feat: add in packet with all dependencies

feat: remove unnecessary in packet converter

feat: move move packet to entities namespace

feat: allow nullables in converters

feat: add base packet types converting