Migrate Elyra extensions to support JupyterLab 4.x

[lresende]

What changes were proposed in this pull request?

Migrate Elyra extensions to support JupyterLab 4.x

Fixes #3137

How was this pull request tested?

Building and running on JupyterLab 4.x

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[lresende]

I have made some progress here, but I would appreciate if I could get some help on the UI pieces, in particular on UI-components... @marthacryan @karlaspuldaro @ajbozarth and others feel free to send prs to this branch as time permits... I completely understand if you are not able to.

[hadesto]

hello! is this pull request still being worked on? it would be amazing to have support for JL4 now that JL3 has an official sunset date. Is there any support required from the community? Thank you!

[lresende]

There is a pr against this pr, let me merge that over the weekend and then others can jump in to help finish any remaining items

[hadesto]

thanks for the quick response!

[ederign]

hi @lresende, thank you so much for this work! Where are these 'remaining items' located? I would love to figure out ways to help! (at least testing it)

[harshad16]

thank you so much for this work! Where are these 'remaining items' located? I would love to figure out ways to help! (at least testing it)

@ederign they are opened as PR to the branch, here: https://github.com/lresende/elyra/pull/1