chore: update packets version

docs(packets): add missing documentation

feat(packets): add missing hitmode

feat: make projects available for netstandard 2.1

feat(packets): add entities and maps packets

chore: add repository url and license to nuget

docs: add documentation for missing fields

chore: add nuget description

fix(packets): use skill vnum instead of id to avoid confustion between cast id and skill vnum

fix(packets): make correct fields nullable

fix(packets): make cmode morph skin allow higher values

feat: split packets definitions into separate assembly