Move frontend dev dependencies out of production dependency list.

What does this MR do?

1. Moves webpack-dev-server and karma-mocha-reporter into devDependencies since they are not needed in production.
2. Relaxes strict semvers in for other assets in project.json since we now lock them down in yarn.lock.

Are there points in the code the reviewer needs to double check?

After installing node modules with yarn install --pure-lockfile, the output of yarn check should show no errors ("dedupe" warnings are fine -- that is a separate issue).

Why was this MR needed?

This will allow us to upgrade our dependencies more easily in the future and use semver the way it is meant to be used.

see: https://docs.npmjs.com/misc/semver#caret-ranges-123-025-004

Screenshots (if relevant)

n/a

Does this MR meet the acceptance criteria?

• [ ] Changelog entry added
• [ ] Documentation created/updated
• [ ] API support added
• Tests
  • [ ] Added for this feature/bug
  • All builds are passing
• Conform by the merge request performance guides
• Conform by the style guides
• Branch has no merge conflicts with master (if it does - rebase it please)
• Squashed related commits together

What are the relevant issue numbers?

n/a