Cobblemon DexRewards

# Dex Rewards v2.0 Is Here!
*The customization update!*

**This update includes a complete rewrite of the mod, so please read the changes very carefully!**

Changes/Additions:
- Removed GooeyLibs dependency.
- Added `config.json`, `rewards.json`, and `messages.json` to the config files.
- Config.json includes various options for full control over what counts towards the pokedex total!
- Rewards.json is the new home for reward groups
- Added optional data component sections for group icons and item reward items.
- Messages.json allows for message customization, and GUI customization
- Gui customization includes modifying the location which player info, groups, background item, and navigation buttons appear, along with the title and size of the GUI.
- Each gui element can also be customized to include whatever content you'd like!
- All messages and gui content supports the use of Kyori MiniMessage formatting!
- Added the following commands:
  - /dex update <player> | `force updates the target player's dex reward progress`
  - /dex reset <player> | `resets the target player's dex reward progress`
  - /dex generate |  `generates json files of every pokemon not marked as implemented in datapacks on the world. This is used to quickly add files to your species additions folder of the datapack.`
  - Permissions: `dexrewards.reload`, `dexrewards.reset`, `dexrewards.update`, `dexrewards.generate`
- Also updated the Placeholders used in PlaceholderAPI! Please look at the Wiki for changes

**Note:** I have not tested to make sure that player data from previous versions transfers properly, *however*, I did not change anything about the format or location of the player data, so it should be fine!

**Also Note:** You may need to regenerate your config files, be sure to save your reward groups before you do this so you don't lose them!