Replacing webpack by ESBuild for client code compilation (as in the official quickstart plugin). So we can remove deprecated webpack dependencies. Note: webpack is still used for ConverseJS build. This may be removed soon. Related to issue #122.
Removing old modes (ConverseJS and External URI). Work in progress.
WIP on a new feature: trying to guess current Peertube theme's colors, and apply them to ConverseJS.
