Remove superfluous lib: true, type: redis, service: true, models: true, services: true, no_db: true, api: true

Signed-off-by: Rémy Coutable <remy@rymai.me>

When sign-in is disabled:
 - skip password expiration checks
 - prevent password reset requests
 - don’t show Password tab in User Settings
 - don’t allow login with username/password for Git over HTTP requests
 - render 404 on requests to Profiles::PasswordsController

This test and its context exist only to ensure this behavior is fixed: https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/11259#note_29262426

If internal auth is disabled and LDAP is not configured on the instance,
present the user with a message to create a personal access token if his
Git over HTTP auth attempt fails.

And refactor to self-document a little better.

* The spec has 7 failures at this point
* Specify rendered error messages
* Render the GitAccess message rather than “Access denied”
* Render the Not Found message provided by GitAccess, instead of a custom one
* Expect GitAccess to check the config for whether Git-over-HTTP pull or push is disabled, rather than doing it in the controller
* Add more thorough testing for authentication
* Dried up a lot of tests
* Fixed some broken tests

Signed-off-by: Rémy Coutable <remy@rymai.me>

Signed-off-by: Rémy Coutable <remy@rymai.me>

It uses a user activity table instead of a column in users.
Tested with mySQL and postgreSQL

- We currently support fetching code with username = 'oauth2' and
  password = <access_token>.
- Trying to _push_ code with the same credentials fails with an authentication
  error.
- There's no reason this shouldn't be enabled, especially since we allow the
  OAuth client to create deploy keys with push access:

  https://docs.gitlab.com/ce/api/deploy_keys.html#add-deploy-key

Gitlab::Auth.find_with_user_password is currently used in these places:

- resource_owner_from_credentials in config/initializers/doorkeeper.rb,
  which is used for the OAuth Resource Owner Password Credentials flow

- the /session API call in lib/api/session.rb, which is used to reveal
  the user's current authentication_token

In both cases users should only be authenticated if they're in the
active state.

This reverts commit cb10b725c8929b8b4460f89c9d96c773af39ba6b.

https://gitlab.com/gitlab-org/gitlab-ce/issues/24007

- This module is used for git-over-http, as well as JWT.

- The only valid scope here is `api`, currently.