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.

Hermann authored 6 years ago and Sandro Lutz committed 6 years ago

so far, FormData submit did not support multiple values per key. We need this for studydocuments.
Therefore, submit now simple takes a FormData or Object as input and patches it to the resource.