Add a "user_show_add_ssh_key_message" application setting for use with SSH certificates

Closes #49953

See merge request gitlab-org/gitlab-ce!21027

it will decide the method for disable statement_timeout upon
per transaction or per session, based on how it's called.

When calling with a block, block will be executed and it will use
session based statement_timeout, otherwise will default to existing
behavior.

This fixes gitlab-org/gitlab-ce#49953, as noted in the documentation
this feature is intended to be used when SSH certificates are
enabled. Then this warning becomes not only pointless, but also
misleading.

This builds on top of gitlab-org/gitlab-ce!21009 since both need to
modify the same documentation, which avoids a merge conflict.

See also the gitlab-org/gitlab-ce#49218 issue and associated merge
request.

Remove redundant ci_builds (status) index

See merge request gitlab-org/gitlab-ce!21070

This enables JavaScripts projects to have live previews straight in the
browser without requiring any local configuration. This uses the
CodeSandbox package `sandpack` to compile it all inside of an iframe.

This feature is off by default and can be toggled on in the admin
settings. Only projects with a `package.json` and a `main` key are
supported.

Updates happen in real-time with hot-reloading. We just watch for
changes to files and then send them to `sandpack` to allow it to reload
the iframe. The iframe includes a very simple navigation bar, the text
bar is `readonly` to stop users navigating away from the preview and
the back and forward buttons just pop/splice the navigation stack
which is tracked by a listener on `sandpack`

There is a button inside the iframe which allows the user to open the
projects inside of CodeSandbox. This button is only visible on
**public** projects. On private or internal projects this button
get hidden to protect private code being leaked into an external
public URL.

Closes #47268