feat(ux): a11y: add focus outline

Ghost Userrequested to merge
(removed):2235-conference-focus-outlines into main

Includes adjustments to UI so outlines are visible as well as a few reworks (most notably poll/votes popover) for increased accessibility.

Commits are structured for visibility during reviews, will rebase everything into one singular conventional commit once we finalize development.

Co-authored by @e.neumann, @v.staikov

Closes #2235, #2236, #2237

Edited by Ghost User

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