feat: add custom `commands.Context` with utilities attached

[WieeRd]

Bring back the "MacLak" classes from ClockBot v3.

• Type hint overrides for different contexts (guild only, DM only, etc.)
• feat: add SendExt to reduce boilerplate of common send() calls #4
• feat: automated webhook management and caching #13
• tick(bool) - Add ✔️ or ❌ reaction
• Add random tips to the embed footer