Add lightweight built-in anti-spam system to EssentialsXChat #6638

Feature description

I propose adding a native, lightweight anti-spam system directly into EssentialsXChat. It should include basic moderation mechanics to keep chat clean without needing third-party plugins.

The core features should include:

• Chat Cooldown: A configurable delay (in seconds) between messages with a bypass permission (essentials.chat.bypass.cooldown).
• Duplicate Filter: Blocking identical or highly similar repetitive messages from the same player.
• Caps Lock Filter: Automatically converting text to lowercase if a message contains too many capital letters (e.g., >70% CAPS).
• Automated Actions: Configurable responses when spam is detected (block message, warn player, or run a command).

How the feature is useful

• Eliminates Formatting Conflicts: A native solution ensures 100% compatibility with EssentialsXChat formats, prefixes, and suffixes.
• Reduces Server Lag: Built-in features require fewer event listeners, saving server resources compared to running heavy external plugins.
• Centralized Configuration: Server owners can manage formatting, local chat, and spam prevention inside a single config.yml file.
• Instant Protection: Provides new server administrators with baseline chat moderation right out of the box.

Note: This request was written using a translator, so it may contain minor grammatical errors.