Add Ukrainian localization file uk.yml

Closes: #337

who don't follow them

Do not autoplay videos, display play button instead. Use expiring links when using S3. Do not keep originals
for avatars/headers, resize avatars down to 120x120 instead of 300x300. Set cache headers on S3 stuff, also
make it private (aka only accessible via expiring links to prevent hotlinking)

Add Ukrainian localization file doorkeeper.uk.yml

Closes: #334

(without avatar). Also improved search position of exact matches

Replace “Unlisted mode” with “Do not show on public timeline”

Fix line endings for Portuguese locale

from accounts/tags because it's a terribly inefficient way to paginate
large sets of data

Devise, Doorkeeper, settings & general PT translation