This adds an ID-less table containing one row per file, per merge request
diff. It has a column for each attribute on Gitlab::Git::Diff that is serialised
currently, with the advantage that we can easily query the attributes of this
new table.

It does not migrate existing data, so we have fallback code when the legacy
st_diffs column is present instead. For a merge request diff to be valid, it
should have at most one of:

* Rows in this new table, with the correct merge_request_diff_id.
* A non-NULL st_diffs column.

It may have neither, if the diff is empty.

Create a post-deployment migration to update all existing notification settings
with at least one custom level enabled to the new format. Also handle the same
conversion when updating settings, to catch any stragglers.

Fix https://gitlab.com/gitlab-org/gitlab-ce/issues/27070

Deprecate "chat commands" in favor of "slash commands"

We looked for things like:

 - `slash commmand`
 - `slash_command`
 - `slash-command`
 - `SlashCommand`

Older pipelines can contain jobs without a name, in which case
'nameless' is used right now, so we can properly still handle other
actions on these jobs.

Fixes gitlab-org/gitlab-ce#33403

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

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

Detect if file that appears to be text in the first 1024 bytes is actually binary afer loading all data

Ran:
 - git format-patch v9.2.2..v9.2.5 --stdout > patchfile.patch
 - git checkout -b 9-2-5-security-patch origin/v9.2.2
 - git apply patchfile.patch
 - git commit
 - [Got the sha ref for the commit]
 - git checkout -b upstream-9-2-security master
 - git cherry-pick <SHA of the patchfile commit>
 - [Resolved conflicts]
 - git cherry-pick --continue

Ran:
 - git format-patch v9.2.2..v9.2.5 --stdout > patchfile.patch
 - git checkout -b 9-2-5-security-patch origin/v9.2.2
 - git apply patchfile.patch
 - git commit
 - [Got the sha ref for the commit]
 - git checkout -b upstream-9-2-security master
 - git cherry-pick <SHA of the patchfile commit>
 - [Resolved conflicts]
 - git cherry-pick --continue

Previously, `PagesDomain` would not allow a domain such as
123.example.com. With this change, this is now allowed, because
it is a perfectly valid domain.

This is the first commit doing mainly 3 things:
1. create a new scope and allow users to use it
2. Have the JWTController respond correctly on this
3. Updates documentation to suggest usage of PATs

There is one gotcha, there will be no support for impersonation tokens, as this
seems not needed.

Fixes gitlab-org/gitlab-ce#19219

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

So we don't have to do it in CreateDeploymentService
Feedback:
https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/11695#note_31322649

When a new deployment is created, this will trigger the invalidation on
the etag cache on the environment. This flow is now explicitly tested.

To make sure that we're accessing the same instance, so ending up
with `env.external` = `env.external_url` shall be fine.