Enable customizable bot banners

[suchet11]

I believe the ability to customize bot banners would offer several benefits:

Improved branding and communication: Bots could use their banners to display logos, slogans, or other visual elements that represent their brand and purpose. This would help users more easily understand the bot's function and build trust.
Enhanced user experience: Custom banners could be used to provide important information to users, such as instructions on how to use the bot, links to its documentation, or upcoming updates. This would make interacting with bots more intuitive and efficient.
Increased creativity and competition: Allowing developers to customize their banners would encourage them to be more creative and innovative in their bot design. This could lead to a wider range of more engaging and useful bots for users.

[TwilightZebby]

Dupe of #3356 me thinks