Add jupyterlab-new-launcher extension

[krassowski]

Reference Issues or PRs

• META - Design a better JupyterLab launcher conda-incubator/conda-store-ui#255
• https://github.com/nebari-dev/jupyterlab-new-launcher

(for now this is a draft for testing the image including jupyterlab-new-launcher, and also for awareness)

What does this implement/fix?

Put a x in the boxes that apply

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds a feature)
• Breaking change (fix or feature that would cause existing features not to work as expected)
• Documentation Update
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no API changes)
• Build related changes
• Other (please describe):

Testing

• Did you test the pull request locally?
• Did you add new tests?

Documentation

TBD

[krassowski]

Resolved conflicts. I think v0.3.0 should be mature enough to include in the next pre-release.

[marcelovilla]

LGTM. Thanks @krassowski!