1.14 support, (sub)command tabcomplete

[NorbiPeti]

• Made SpawnComponent, with Multiverse and BungeeCord support
  • Fixed other players getting teleported (#75)
• Async command processing (except the actual command execution)
• Bunch of 1.14 issues fixed (mostly async events)
• Removed reference to IOUtils
• Made the config name warning test only
• Towny fix
• Dependency updates
• CI fix
• Update to Java 11
  • Using Jabel to compile to Java 8
  • Removed jitpack.yml so it builds with the Maven target
• Created a parent POM so things like Jabel and Lombok don't need to be set up or updated everywhere