* add og:url to stream_item view

* add og:url and text to about/show

* add og:url to profile, followers and follows pages

* Add meta tags for OGP to following & follow page

* simplify render helper

* Follow up #2133

* og:type is only accounts/show

* revert accounts/{following,followers}

* Simplify render in mailer views

* Simplify render in about/more view

* Simplify render in accounts follow views

* Simplify render in recovery code views

* Simplify render in stream entry embed

* Simplify render in stream entries status partial

* Simplify render in authorize follow new view

* Move site title helper to instance helper (name change only)

* Remove newline in <title> tag

* Add site_hostname helper method to wrap up local_domain value

* Use site_hostname helper in places that need local_domain value

* Use local vars in accounts/header partial

* Use local variable in 2fa recovery codes partial

* Add option to disable verify partial doubles

* Add show_landing_strip? helper method

* Use show_landing_strip? helper in accounts and stream entries views

* Fix naming in view specs

An attempt to open a brand new Mastodon instance configured
as SINGLE_USER_MODE=true will cause an exception.

Enable temporary registration if we have no users in the database

Fixes #1817

* Replace will_paginate with kaminari

* Use #page instead of #paginate in controllers

* Replace will_paginate.page_gap with pagination.truncate in i18n

* Customize kaminari views to match prior styles

* Set kaminari options to match prior behavior

* Replace will_paginate with paginate in views

* Add helper method to return Setting.site_title

* Use site_title helper in application layout

* Use site_title value for og:site_name

h-feed, h-card and h-entry

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