Offer "expand all" and store what was expanded across page refreshes

Description

The UI always collapses sub-pipelines in an effort to simplify the pipeline. But this makes it hard to see the whole picture easily.

Pipeline(
        [
            Node(
                lineage_creation_node, 
                inputs=["raw.lineage_data"], 
                outputs=["int.lineage", "int.lineage_mapping"],
                name="lineage_creation"
            ),
            Node(
                # TODO kedro: this actually does process data -> should be int/prm output
                process_raw_redshift_data,
                name="process_raw_redshift_data",
                inputs={
                    "b_df": "raw.redshift.b_df",
                    "a_df": "raw.a_df",
                    },
                outputs=["int.combined_redshift_data"]
            )
        ]
    )

(sanitised the code a bit)

and the UI collapses them and puts them next to the functions. Only when I expand all layers in the UI is the structure as expected

Context

It would be nice to have the possibility to keep the pipeline expanded between page reloads. This way, I can use --autoreload and watch the pipeline’s progress while developing and also not have to manually expand every single subpipeline / layer combo.

Possible Implementation

Possible Alternatives

Checklist

• Include labels so that we can categorise your feature request

[datajoely]

I would personally love a button to expand everything to the max, but that’s not as high priority

[tynandebold]

This feature is now released! Toggle the Expand all modular pipelines flag on in the settings panel.