Use YAML for Velocity config

Note: This issue is VERY early, and any code snippets shown are hypothetical, subject to change, and aren't guaranteed to work without other code modification (where applicable).

As the title states, this issue proposes the use of YAML over HOCON as the transition to completely use Configurate begins. While many may prefer the use of HOCON over the use of YAML, HOCON is currently limited on how sorting is done (by hashcode (thanks zml)). I believe that it is critical we maintain the order of config options to ease confusion on server admin/owner(s) and keep the same clean appearance that we are all used to.

I have experimented with both options, links to each are below, and believe that YAML is the best option on the market at the time of writing. With that being said, there is always the possibility of advancements in HOCON that will allow us to control the order of the config. Along with this, I do plan on writing an example converter for converting the TOML to YAML if necessary.

YAML
HOCON

(comments are currently missing, but can be added as progression is made)
YAML Config
HOCON Config

No source files, tests, or entry points are named. Start by locating Velocity's current HOCON and Configurate handling, then review the linked YAML and HOCON examples. Done would require an agreed migration scope and implementation plan, including whether a TOML-to-YAML converter is needed.