Add ability to search accounts by display name

Text for link to other instances

to only those from local users; Add link to "extended information" to
getting started in the UI; Add defaults for posting privacy; Change
how publish button looks depending on posting privacy chosen

Federate spoiler_text using warning attribute on <content /> instead of a <category term="spoiler" />
Clean up schema file from accidental development migrations

application website validation, don't link to app website if website isn't set,
also comment out animated boost icon from #464 until it's consistent with non-animated version

A couple of places were using "reblog" rather than "boost" - this updates them to match the web UI

Better initial state for unlisted/nsfw toggles

coming in via Salmon.

Currently no way to prevent remote follows, but they will only receive public
and unlisted posts

Reflect "requested" relationship in API and UI
Reflect inability of private posts to be reblogged in the UI
Disable Webfinger for locked accounts

fix #361 with rich OEmbed display via iframe, fix #237 by hiding sensitive
content behind a spoiler on public pages

Closes: #337

Closes: #334

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

Fix #233, fix #268

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