Conflicts:
	app/models/ci/pipeline.rb
	app/models/commit_status.rb

This solves Pipelines in `running` after all stages do finish.

This reverts commit 575dc2b0.

Because pipeline status could be changed for the builds in the next
stages, if we process next stages first, the current build would be
out of synchronized, and would need a reload for that matter.

Alternatively, like what I did in this commit, we could process the
next stages later (by using `after_transition` rather than
`around_transition`), and complete what're doing for the current
build first. This way we don't have to reload because nothing is
out synchronized.

Note that since giving `false` in `after_transition` would halt the
callbacks chain, according to:

https://github.com/state-machines/state_machines-activemodel/blob/v0.4.0/lib/state_machines/integrations/active_model.rb#L426-L429

We'll need to make sure we're not returning false because we don't
intend to interrupt the chain.

This fixes #22010.

After this fix, both pipeline events and build events would only show
up once.

This change simplifies a Pipeline processing by introducing a special new status: created.
This status is used for all builds that are created for a pipeline.
We are then processing next stages and queueing some of the builds (created -> pending) or skipping them (created -> skipped).
This makes it possible to simplify and solve a few ordering problems with how previously builds were scheduled.
This also allows us to visualise a full pipeline (with created builds).

This also removes an after_touch used for updating a pipeline state parameters.
Right now in various places we explicitly call a reload_status! on pipeline to force it to be updated and saved.

This version of MySQL doesn't yet support 'LIMIT & IN/ALL/ANY/SOME
subquery'

Oh well.

https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/5142#note_13047163

So that we could find the particular builds according to
build_name and ref. It would be used to find the latest
build artifacts from a particular branch or tag.

This reverts commit 3e991230.

# Conflicts:
#	app/models/project.rb

When a build fails for a commit, create a todo for the author of the
merge request that commit is the HEAD of. If the commit isn't the HEAD
commit of any MR, don't do anything. If there already is a todo for that
user and MR, don't do anything.

Current limitations:
- This isn't configurable by project.
- The author of a merge request might not be the person who pushed the
  breaking commit.