MVP for the application manager

[jaimergp]

A minimally functional application manager should do the following:

• Check new updates on Github and conda-forge releases. Notification dialog can probably reuse PartSeg's checker. This will go first in napari-plugin-manager. Then maybe duplicated in constructor-application-manager at start time. @goanpeca
  • Note that we shouldn't notify the user if the most recent version found is already installed (e.g. in the case of the user running an older napari for reproducibility purposes).
  • Add initial package structure update-checker#1
  • Publish package
  • Add to menuinst JSON flags
• Install new napari environments from conda lockfiles published to Github Releases for maximum reproducibility.
  • Generate explicit lockfiles per environment conda/constructor#898
  • Generate lockfiles for the constructor envs #201
  • Have NAM install from the lockfile for new installs
• Import / Export list of plugins to a file in napari plugin manager to NAM can reuse it napari-plugin-manager#116
  • Add import/export functionality and buttons on ui napari-plugin-manager#120
• Migrate settings.yaml files from version to version. #206