Prc.api

Adds support for new set of PRC ER:LC private server API commands (`:helper` commands), including typings and built-in server command methods.

**Notable changes** since last beta release:
1. [`Vehicle.full_name` as property](https://github.com/Tycho-Systems/prc.api/commit/a8c6c30d3852b8408975d0ef1aacb89cdab76a48)
2. ⚠️ [redefine `ModCallEntry.is_acknowledged` as a method](https://github.com/Tycho-Systems/prc.api/commit/cad4434c0721578a651e5cd08a00cb6eb1fc5b05)
3. ⚠️ `JoinEntry.is_join` -> `JoinEntry.joined`
4. Added more docstrings.

**All Changes**: https://github.com/Tycho-Systems/prc.api/compare/v0.1.2...v0.2.0

Fixes a critical bug caused by a missing init script for server models.

Initial beta release of `prc.api`!