* Add Admin::BaseController to wrap admin area

Extracts the setting of the `admin` layout and verifying that users are admins
to a common base class for the admin/ controllers.

* Add basic coverage for admin/reports and admin/settings controllers

Sign-in redirects you back to last visited URL, but in case of API requests,
this sometimes redirected users to an API URL that, of course, greeted them
with an {"error":"The access token is invalid"}

* Use HTTP Accept-Language to detect locale

* Fix gem order to comply with codeclimate

* Sort gem to comply with rubocop

* I18n.default_locale fallback when there is no accept-language header

* Allow users to update their Account in the API

It would be nice for API clients to be able to allow users to update
their accounts without having to wrap Mastodon in a web view. This patch
adds an API endpoint to let users submit a PATCH for their account.

Signed-off-by: David Celis <me@davidcel.is>

* Add /api/v1/accounts/update_credentials to the API docs

Signed-off-by: David Celis <me@davidcel.is>

* Add InstancePresenter to expose site details

* Clean up about controller, use instance presenter

* Make /api/v1/timelines/public and /api/v1/timelines/tag/:id public
Fix #1156 - respect query params when generating pagination links in API

* Apply pagination fix to more APIs

* Fix #795, fix #704, fix #835 - 2FA requires confirmation to be enabled
TOTP secret is not shown again after 2FA is enabled

* Clean up

Setting of locale in controller extracted to Localized concern,
the doorkeeper authorized applications controller moved under
custom namespace with inclusion of Localized, which resolves the
"it sometimes appears in a different random language" bug

* Rewrite Atom generation from stream entries to use Ox instead of Nokogiri::Builder

StreamEntry is now limited to only statuses, which allows some optimization. Removed
extra queries on AccountsController#show. AtomSerializer instead of AtomBuilderHelper
used in AccountsController#show, StreamEntriesController#show, StreamEntryRenderer
and PubSubHubbub::DistributionWorker

PubSubHubbub::DistributionWorker moves n+1 DomainBlock query to PubSubHubbub::DeliveryWorker
instead.

All Salmon slaps that aren't based on StreamEntry still use AtomBuilderHelper and Nokogiri

* All Salmon slaps now use Ox instead of Nokogiri. No touch from status on account

This stores the @username@instance you provide in your session and
reuses it the next time you remote follow someone from this instance.

reports for that user automatically

admin UI

Returns accounts, statuses, hashtags arrays

(Because postgres can tell that count(*) needs no extra checks, but
counting a specific column requires them)

Redirect /:username to /users/:username
Redirect /:username/:id to /users/:username/updates/:id
Updated API documentation and sponsors

Add ability to search accounts by display name

make status pagination headers generation more lax about next page
existing

Using catch statement in api_controller.rb to catch NotPermitted
Exception, and render error message

Moved validation to services/post_status_service.rb

Modified uploadCompose action to send media ids of attached
media when sending a request. Modified create method in MediaController
to check if when posting a video, there are no other media attached
to the status by looking at the media ids sent from the uploadCompose
action.

Make replies default to privacy settings of the status being replied to