Merge kedro pipeline and kedro registry

[astrojuanlu]

Description

(Comes from Slack)

Since kedro pipeline and kedro registry are both somewhat related to the pipeline registry, I propose we merge both to have

• kedro pipeline list (formerly in kedro registry)
• kedro pipeline describe (formerly in kedro registry)
• kedro pipeline create
• kedro pipeline delete

and therefore deprecate, and eventually remove, kedro registry.

@merelcht points out that "We’d need to clearly define what the difference is between a “registered” pipeline and just pipelines that exist, but aren’t part of any run command e.g. if the user has changed what’s run by default".

Context

I was trying to get a list of available pipelines, which was available behind kedro registry but not kedro pipeline.

[yetudada]

This ticket is a little tricky to address because it refers to how things in Kedro are named. We needed a way to refer to the different pipelines that users could create.

There's a difference between this:

And this:

We named the first image of "pipelines" - "registered pipelines" - because users would need to interact with the pipeline_registry.py. But you'll observe that a "registered pipeline" is not the same as a "modular pipeline" which is what is present in the second image. This is why the CLI commands are split because they refer to different things when used e.g. kedro pipeline create <pipeline_name> is used to create a modular pipeline but not a registered pipeline.

So we don't know how to fix this, it's less intuitive than it should be.

[astrojuanlu]

I now understand that these two should not be merged. If anything, we could have a kedro pipeline list that lists all the pipelines (even non-registered ones), but we should assess how useful this would be.