Switch client API wrapper library from discord.py to PyCord

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Moving from discord.py to PyCord

As you might know, all NKA bots (including my own bots) are switching from discord.py to PyCord. This change was delayed as the project was abandoned a little, but now since the bot is back to development phase, I am switching it.

The advantage of using PyCord is simple: speed, reliability, features.

• Speed: Increases snappiness of slash commands by using a built-in system, rather than combining and using multiple ones.
• Reliability: The problem of mismatched library versions and command failures are now greatly reduced.
• Features: PyCord includes new and direct support for new Discord API features without having to use external libraries.

As well as all of these, Discord has removed direct support for prefix commands, which makes it a more sensible decision to switch to slash commands.

This is why we are switching from discord.py to PyCord.

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Fun fact: This proposed update also helped with debloating the code by removing duplicate commands of different types, and minimising the number of class instances and modules needed.