Will clear the browser's cache, cookies and storage.

https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Clear-Site-Data
https://w3c.github.io/webappsec-clear-site-data/

* Allow moderators to disable/enable login

* Instead of rejecting login, show forbidden error when login disabled

Avoid confusion because when login is rejected, the message is that
the account is not activated, which is wrong.

* Fix tests

* Compensate for scrollbar disappearing when media modal visible

Make auth pages backgrounds lighter

* Fix typo

Fix #6670

* add pam support, without extra column

* bugfixes for pam login

* document options

* fix code style

* fix codestyle

* fix tests

* don't call remember_me without password

* fix codestyle

* improve checks for pam usage (should fix tests)

* fix remember_me part 1

* add remember_token column because :rememberable requires either a password or this column.

* migrate db for remember_token

* move pam_authentication to the right place, fix logic bug in edit.html.haml

* fix tests

* fix pam authentication, improve username lookup, add comment

* valid? is sometimes not honored, return nil instead trying to authenticate with pam

* update devise_pam_authenticatable2 and adjust code. Fixes sideeffects observed in tests

* update devise_pam_authenticatable gem, fixes for codeconventions, fix finding user

* codeconvention fixes

* code convention fixes

* fix idention

* update dependency, explicit conflict check

* fix disabled password updates if in pam mode

* fix check password if password is present, fix templates

* block registration if account is maintained by pam

* Revert "block registration if account is maintained by pam"

This reverts commit 8e7a083d65.

* fix identation error introduced by rebase

* block usernames maintained by pam

* document pam settings better

* fix code style

When case insensitivity is enabled via devise's `config.case_insensitive_keys` then `.find_for_authentication` method needs to be used instead of `.find_by` because second mentioned returns `nil` when valid email with different cases is passed.

More info https://github.com/plataformatec/devise/wiki/How-To:-Use-case-insensitive-emails

In single user mode, visitors are redirected to the single user's
profile page.  So, if you are the owner without a session, you start
from that page, click the login button and authenticate yourself
expecting you'll soon get started with the home page, but in reality
you'll get redirected back to where you started from -- your own
profile page.

This fixes the behavior by redirecting you home after login if you
have started from your own profile page.

* Add a spec for signing out

* Add spec showing that suspended user gets a 403 forbidden on sign out

* Allow suspended account users to sign out

* disable Bundler/OrderedGems

* fix rubocop Lint/UselessAssignment

* fix rubocop Style/BlockDelimiters

* fix rubocop Style/AlignHash

* fix rubocop Style/AlignParameters, Style/EachWithObject

* fix rubocop Style/SpaceInLambdaLiteral

* Add recovery code support for two-factor auth

When users enable two-factor auth, the app now generates ten
single-use recovery codes. Users are encouraged to print the codes
and store them in a safe place.

The two-factor prompt during login now accepts both OTP codes and
recovery codes.

The two-factor settings UI allows users to regenerated lost
recovery codes. Users who have set up two-factor auth prior to
this feature being added can use it to generate recovery codes
for the first time.

Fixes #563 and fixes #987

* Set OTP_SECRET in test enviroment

* add missing .html to view file names

registration API