Introduce command trees; improve Commandessentials

[mdcfe]

Information

This PR closes an internal goal.

Details

Proposed feature:

This implements two separate features (may be split into separate PRs later down the line):

• [x] Introduce command trees, which allow for nested subcommands to be declared and parsed effectively.
  • Goals: lightweight, incrementally adoptable across new and existing commands as necessary
  • Trees consist of a root node, literal nodes and execute nodes
  • No parsing of argument types is implemented at present
  • Possibly worth exploring cloud/another tree command lib instead of rolling our own
  • [ ] Provide helper methods on command exec context to replicate EssentialsCommand
  • [ ] Think about command node impl in more depth
• [ ] Rewrite /essentials, splitting complex subcommands into separate classes
  • [x] Replace run and tabComplete impls with tree
  • [ ] Refactor existing subcommand functions
  • [ ] Split out dump into own class (possibly a separate refactor on its own?)

Environments tested:

OS: Windows 11 22H2

Java version: Eclipse Temurin 17.0.6

• [x] Most recent Paper version (1.19.4, git-Paper-547)
• [ ] CraftBukkit/Spigot/Paper 1.12.2
• [ ] CraftBukkit 1.8.8

Demonstration:

This PR should preserve all existing functionality of /essentials.

[YanisBft]

Dumb question maybe, but wouldn't it be possible to use Mojang's brigadier library for this purpose?

[JRoy]

Dumb question maybe, but wouldn't it be possible to use Mojang's brigadier library for this purpose?

Using that severely limits the flexibility we have and reduces the code quality.