Introduces a new status for builds between :created and :pending
that will be used when builds require one or more prerequisite
actions to be completed before being picked up by a runner
(such as creating Kubernetes resources before deploying).
The existing :created > :pending transition is unchanged, so
only builds that require preparation will use the :preparing
status.
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.
