A list of small improvements

[fcollonval]

• Fix dep wrongly specified as dev deps
• Restore CSS scoping
• Reduce diff due to format per Vidar comment
• Restore getMergedValue
• Improve integration tests config
  • Reduce the test matrix (no point to test multiple Python)
  • Test the package installed from wheel not dev
  • Remove unused ref snapshots
• Add integration test for checking resolved conflict download
• Symlink example to ui test to avoid content duplication
• Instantiate editor registries only once (propagate them from top to bottom to reuse tokens in lab)
• Improve API by switching to object instead of args array in all places changes were needed to the API
• Don't clean the favicon when running npm run clean
• Fix lumino and lab styles not being deduplicated in the webapp (the app is much more reactive and FF stops crashing when using the dev tools)
• Use only prebuilt lab extension
• Modernize Jest config

[fcollonval]

cc @krassowski for awareness

[krassowski]

If that helps I have the actions enabled on my master branch, so the new snapshots can be grabbed from krassowski#5 (or by opening a PR and triggering bot via comment to get them directly).

[fcollonval]

Thanks a lot Mike, I'll take the new snapshots from your branch.