✨ [feat] Added `/makestage`; modified Customization cog commands and more

[hitblast]

This PR synchronizes IgKnite's codebase with the recent major release of disnake (version 2.9.0).

Things changed:

• [x] Added a new /makestage slash command which can be used to create new stage channels.
• [x] Renamed the /makevc command to /makevoice.
• [x] Moved the /slowmode command from the Moderation cog to the Customization cog.
• [x] Channel creation commands now have a new slowmode parameter which can be used to set an optional, custom slowmode delay for the specific channel.
• [x] The /deletechannel slash command can now delete category channels as well.
• [x] Reinclude Pylance and Black as default language servers and formatters. Use Ruff in parallel.