External Jar Loading of Skills

[Zidane]

Skills core loads Skill types from xml files but does not load the logic (basically the listener code). Original idea was to do this all in xml but that became a pipe dream and too inflexible/incomprehensible for admins. Right now to make this work for the Almura server Skills has a BuiltinModule on top of the core that loads core logic:

https://github.com/AlmuraDev/Skills/blob/api-7/src/main/java/org/inspirenxe/skills/impl/content/type/skill/builtin/BuiltinEventListener.java

Here is a brain dump of things that will come up with implementing this:

• What is an external skill to us?
  • Is it just another plugin?
  • If not a plugin, what do we allow them to do with access to the API?
    • We could inject the SkillAPI impl's PluginContainer and have the dev to register everything underneath it.
• Need a standard setup to work on an external skill.
  • These would have a dependency on the SpongeAPI as well as the SkillAPI.
• What metadata do we require in the external skill jar?
  • Having the Skill xml in the jar file would do I think.
• Need a way to determine the id of the external Skill.
  • Could just have these all with the "skills" domain that way two skills named "mining" wouldn't be loaded.
    • Granted one could argue that should be allowed if they are different.
• How much should the SkillAPI attempt to add to make writing listener code easier?
  • Right now the repo contains a "chain system" for constructing a quick way to add entries for us to cancel events, award xp/money, and send messages/effects. This could be useful to others but is quite in-flexible for advanced usecases.