This dogfood artifacts and download the Knapsack report, flaky specs
report, and Crystalball report from the latest successful master
pipeline triggered by @gitlab-bot (this should be a scheduled pipeline
for which we're sure update-tests-metadata was run).

This also remove the need to upload these reports to S3 since they're
already uploaded as artifacts.

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

This reverts merge request !46424

This dogfood artifacts and download the Knapsack report, flaky specs
report, and Crystalball report from the latest successful master
pipeline triggered by @gitlab-bot (this should be a scheduled pipeline
for which we're sure update-tests-metadata was run).

This also remove the need to upload these reports to S3 since they're
already uploaded as artifacts.

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

The previous URL had two drawbacks:

1. It didn't match what the title was about (`Assignments to DevOps
   Stages and Groups`, and the anchor was `#designated-technical-writers`).
2. It didn't account for the other sections, like development and API
   guidelines.

Yet more pages that need to be marked as "none" for stages.

This reverts merge request !46321

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

Also, consolidate the Knapsack report into a single file, and
consolidate the RSpec EE-specific job from the RSpec base job.

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

I noticed the doc/development/testing_guide/best_practices.md still
referenced the `[run mysql]` tags, etc. They no longer work, so I
removed them, then realised I had better clean up the rest of
doc/development !

Also fixes instances in Markdown that broke the rule.

This reverts commit 676e0a32.
It was removed when we thought we were moving to Looker.

Related links:

* https://gitlab.com/gitlab-com/Product/issues/5
* https://gitlab.com/meltano/looker/issues/294

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