Remove development dependencies from webui container

[bziemons]

Development dependencies are installed when using npm install without any additional parameters.

containers/webui/Dockerfile

Line 44 in 1cf27e4

RUN npm install

These dependencies bloat the image and increases the general amount of packages and therefore security vulnerabilities in the image.
NPM can be told to not install dev dependencies by using the NODE_ENV environment variable or the --production switch on npm install,
see https://docs.npmjs.com/cli/v9/commands/npm-install?v=true