feat: add moderation commands and update README

- Introduced a new set of moderation commands including `/moderation purge`, `/moderation timeout`, `/moderation kick`, `/moderation ban`, `/moderation unban`, `/moderation untimeout`, and `/moderation slowmode`.
- Updated README to include details about the new moderation features and commands.
- Enhanced help command to display moderation tools and their usage.

internal/commands/moderation/registry.go

@@ -0,0 +1,16 @@
+package moderation
+
+import (
+	"velox-bot/internal/commands/moderation/public"
+
+	"github.com/bwmarrin/discordgo"
+)
+
+var (
+	Moderation *discordgo.ApplicationCommand = public.Moderation
+)
+
+func ModerationHandler(s *discordgo.Session, i *discordgo.InteractionCreate) {
+	public.ModerationHandler(s, i)
+}
+