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

The current "basic" merge request API still loads too much data. For integrations
like the Trello Power-up, we just need the basics.

Closes #34920

Closes #34159

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

This hides/disables some UI elements and API parameters related to
nested groups when MySQL is used, since nested groups are not supported
for MySQL.

Rename `build_events` to `job_events`

Closes #31620

See merge request !11287

This reverts merge request !11287