Upgrades the versions of webpack and related packages and replaces the
optimization in the build process with new methods (same as for
amiv-website instead of uglify-js). Also fixes some new linter errors that appeared because of new eslint-rules.

This caused eventsignups to crash in case of email signups.
Additionally, constructor arguments are now set as object making them better readable.

this comes together with a more unified layout of edit views
the new structure simplifies data handling and needs less api communication, making it more responsive