Upgrade to webpack 5 (#1896)

* chore: upgrade webpack to version 5

* fix: update webpack config for new version

* chore: remove babel-minify-webpack-plugin

* chore: remove license.txt files

* remove library parameter

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Co-authored-by: Marco Link <marco.link@contentful.com>
Co-authored-by: Maya Karabula-Stysiak <maya.karabula@contentful.com>