Quick Reblog: Display blog avatars in blog selector

[marcustyphoon]

User-facing changes

• Adds an option to display avatars beside the Quick Reblog blog selector.

Technical explanation

I threw CSS at the wall until the select element correctly resized. Can you do this without display: flex and flex: none (and a bunch of manual padding)? Probably, but apparently I can't figure out how to.

Quick Reblog could use a bit of a rewrite to use dom().

Issues this closes

resolves #716

[marcustyphoon]

Oh, dammit. I love the hidden property, it's the best.

[AprilSylph]

I think this makes more sense as just how Quick Reblog works rather than a preference. Also yes, please rewrite the entire structure with dom, it's been on my mental to-do list for a while.

[AprilSylph]

I have some CSS changes that I'm just going to commit directly, as the changes touch lines I can't code-suggest on.

Moved the avatar margin to container padding, made the blog selector itself slimmer, and added some space between the avatar and the blog selector so that Chrome's default focus outline for the blog selector doesn't look terrible.

[marcustyphoon]

Quick Firefox screenshot. Looks fine to me!