Add images and videos to docs

[harshil21]

Adds some images and a video to the docs. This was taken from https://core.telegram.org/bots/features.

For the dark mode version of the images, I simply used a invert() on them. If we decide to add more pictures or videos to other places in the docs, we could think about a pure dark and light mode version of each

Build should be up at: https:https://docs.python-telegram-bot.org/en/doc-pictures/

Checklist for PRs

• Added .. versionadded:: version, .. versionchanged:: version or .. deprecated:: version to the docstrings for user facing changes (for methods/class descriptions, arguments and attributes)
• Created new or adapted existing unit tests
• Documented code changes according to the CSI standard
• Added myself alphabetically to AUTHORS.rst (optional)
• Added new classes & modules to the docs and all suitable __all__ s

[Bibo-Joshi]

Nice idea with the automated color scheme preference 👍

[lemontree210]

The docs are getting prettier still :)

1. Why is this PR against master? (Just checking)
2. A clickable image opening in a new tab (leading either to the larger image or even the section of Telegram docs) would be a nice-to-have, but that would mean using that raw html thing you did with the video

[Bibo-Joshi]

Can the DS issue be resolved or is that complaint unreasonable?

[harshil21]

I ignored the Deepsource error within deepsource itself, so hopefully it won't trigger again