Remove references to Jupyterlab 1.x and 2.x from documentation

[ptitzler]

Remove references to Elyra versions that require Jupyterlab v1 (last update 08/21) and v2 (last update 06/21) from the documentation. The main goal is to discourage users from deploying Elyra versions that are no longer under active development.

Signed-off-by: Patrick Titzler ptitzler@us.ibm.com

What changes were proposed in this pull request?

See above.

How was this pull request tested?

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[kevin-bates]

These changes look good. My "grep -ri JupyterLab" exercise did yield another possible change. In the NOTE: and the bottom of this section, we reference a JupyterLab release of 2.2.9 that might give a false impression.

[kevin-bates]

Thanks Patrick and Alan!