Hub Teleport, Testing Mode & PlayerCoords Precision

[psynezo]

This PR introduces several enhancements to LimboReconnect for better player experience and plugin testing:

1. Testing Mode

• Added a testing configuration option for instant Limbo connections.
• When enabled, allows testing plugin functionality and easier configuration of Limbo.

2. Hub Teleport

• Adds a feature that allows instant teleportation to a hub if the server the player was on is unavailable.
• By default, players receive a clickable chat message allowing them to teleport immediately to a hub, avoiding waiting for the original server.
• Supports multiple hub servers and automatically retries if hubs are full.
• Fully configurable through HubTeleport in the config.

3. PlayerCoords Precision

• Updated PlayerCoords from int to double for more precise positioning of players in the Limbo.

4. Supporting Changes

• Updated ReconnectHandler and LimboReconnect to integrate the new Hub Teleport and Testing Mode features.
• Refactored relevant code to support the new features cleanly.

These changes are optional and do not affect default behavior unless enabled in the configuration.
Hub Teleport and Testing Mode are disabled by default.