Refactor admonition component

[damianstasik]

This PR replaces the built-in admonition component. It also removes max-width from docs content (Tailwind's prose), not needed as we have container that does that.

Before:

Light	Dark

After:

Light	Dark

[damianstasik]

Closes #103

[Roma36]

@damianstasik looks awesome, but I'd keep the original color for warning in dark mode. But it's just my taste.

[damianstasik]

@Roma36 as you can see I'm using the orange instead of the yellow as we use it for branding (and it looks bad for admonitions). I was thinking we could rename our yellow to brand and use tailwind's yellow for these admonitions. I just didn't want to introduce any noise.

WDYT?

[Roma36]

@damianstasik I like the approach you propose with introducing brand yellow.

[damianstasik]

@Roma36 here's how it would look like, wdyt?

Dark	Light

[Roma36]

@damianstasik I like that "warning" looks not so "dangerous" now

[damianstasik]

@Roma36 pushed renaming and the actual color change as separate commits, if everything's okay, let's merge it 🚢