Behind an application setting, which defaults to false, this commit
implements the implied CI/CD config. Which means that in the case we
can't find the `.gitlab-ci.yml` on the commit we want to start a
pipeline for, we fall back to an implied configuration.

For now the Bash template has been copied to
`Auto-Devops.gitlab-ci.yml` so the tests actually work.

Fixes #34777

`allowed_key_types` is removed and the `minimum_<type>_bits` fields are
renamed to `<tech>_key_restriction`. A special sentinel value (`-1`) signifies
that the key type is disabled.

This also feeds through to the UI - checkboxes per key type are out, inline
selection of "forbidden" and "allowed" (i.e., no restrictions) are in.

As with the previous model, unknown key types are disallowed, even if the
underlying ssh daemon happens to support them. The defaults have also been
changed from the lowest known bit size to "no restriction". So if someone
does happen to have a 768-bit RSA key, it will continue to work on upgrade, at
least until the administrator restricts them.

This is an amalgamation of:

* Cory Hinshaw: Initial implementation !5552
* Rémy Coutable: Updates !9350
* Nick Thomas: Resolve conflicts and add ED25519 support !13712

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

Remove superfluous lib: true, type: redis, service: true, models: true, services: true, no_db: true, api: true
Signed-off-by: NRémy Coutable <remy@rymai.me>

The implementation now simply rely on the
`performance_bar_allowed_group_id` Application Setting.
Signed-off-by: NRémy Coutable <remy@rymai.me>

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

Setting `usage_ping_enabled` to false in `gitlab.yml`:

1. Disables the usage ping, regardless of the value stored in the database.
2. Prevents the usage ping from being enabled through the admin panel. It can
   only be enabled by either removing the line from `gitlab.yml` and configuring
   through the admin panel, or setting it to true in `gitlab.yml`.

Use the EnforcedStyleForMultiline: no_comma option.
Signed-off-by: NRémy Coutable <remy@rymai.me>

This reverts commit e00fb2bdc2090e9cabeb1eb35a2672a882cc96e9.

# Conflicts:
#	.rubocop.yml
#	.rubocop_todo.yml
#	lib/gitlab/ci/config/entry/global.rb
#	lib/gitlab/ci/config/entry/jobs.rb
#	spec/lib/gitlab/ci/config/entry/factory_spec.rb
#	spec/lib/gitlab/ci/config/entry/global_spec.rb
#	spec/lib/gitlab/ci/config/entry/job_spec.rb
#	spec/lib/gitlab/ci/status/build/factory_spec.rb
#	spec/lib/gitlab/incoming_email_spec.rb

This reverts commit cb10b725c8929b8b4460f89c9d96c773af39ba6b.

https://gitlab.com/gitlab-org/gitlab-ce/issues/27762#note_23520780

in validation. Feedback:
https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/9219#note_23437431
https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/9219#note_23437868

Refactor and rename `restricted_signup_domains` to `domain_whitelist` to better conform to its behavior and newly introduced behavior.

This reverts commit 3e991230.

# Conflicts:
#	app/models/project.rb

stub Devise.omniauth_providers to return GitHub even if the gitlab.yml has no omniauth provider enabled
This will fix failing tests in case gitlab.yml file has no omniauth providers enabled

In 8278b763 the default behaviour of annotation
has changes, which was causing a lot of noise in diffs. We decided in #17382
that it is better to get rid of the whole annotate gem, and instead let people
look at schema.rb for the columns in a table.

Fixes: #17382

I’ve removed everything related to the feature based on this commit:
ce08f919f34fd8849834365

Resolves #10857.

Also:
- Get rid of legacy :strict_mode
- Get rid of custom :email validator
- Add some shared examples to spec emails validation

`max_attachment_size` in `ApplicationSetting` should be present,
only integers greater than zero are valid.

Closes #13188