Follow-up to #6124

- Add follow/unfollow/remote follow buttons
- Format the bio properly
- Always show username@domain, even for local accounts

* Redesign public profiles

* Responsive design

* Change public profile status filtering defaults and add options

- No longer displays private/direct toots even if you are permitted access
- By default omits replies
- "With replies" option
- "Media only" option

* Redesign account grid cards

* Fix style issues

* add haml_lint to Gemfile

* add .haml-lint.yml

* fix warnings of haml_lint

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)

as well as formatting of content

simplify FanOutOnWriteService, add /api/accounts/lookup method

fix tests (the recorded Salmon fixture expects LOCAL_DOMAIN to be something
specific unfortunately)