This change updates the text of the pipeline widget that appears on the
merge request page. The text has been made more consistent between
different types of pipelines; this makes the front-end implementation
simpler and more maintainable.  In addition, the type of pipeline is
(i.e. regular pipeline, merge request pipeline, detached pipeline)
included in the text, making this type more obvious to the end user.

Some information has been removed from the widget as part of this
change; however, any information that was removed already appears
elsewhere on the merge request page.

Align icons left
Align text left
Adjust padding to be consistent
Make icons same 24 size
Add changelog mr number
Add right margin to widget status container
Add left margin inside widget icon container
Prepend left padding for error message
Only give button left margin, some have buttons
Prettify
Adjust test summary icons
Prettify
Fix empty line before lint
Remove author
Switch to use gl-padding
Use utility classes instead
Prettify
Change loading icon size to md
Update summary_row.vue

This reverts merge request !26853

* Add Pipeline IID to MR's
* Add Pipeline IID to commit box
* Add Pipeline IID to builds page
* Add Pipeline IID to job sidebar
* Add Pipeline IID to header on view pipeline pages
* Add changelog entry
* Update tests

This commit prevents the pipeline block to be rendered
when no pipeline information is provided

This commit updates the pipeline block that appears on the merge request
page to include information that will be exposed by the API as part of
the post-merge pipeline feature.

- https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/8593
- Create mr-widget-icon to encapsulate circle icons
- Decouple workflow L&F from mr-widget-heading
- Decouple container L&F from mr-widget-heading

Makes documentation path a required prop

Also:
- Renamed .label-truncated to .label-truncate
- Removed length checking in JS to let the CSS handle this
- Improve IE11 compatibility of MR headers