Moved tooling dependencies to devDependencies

Some dependencies ("@coremedia/cm-cli", "@coremedia/theme-utils", "cross-env", "webpack") used for tooling and building themes have been moved to devDependencies for better clarity. This has no impact to the themes, it's just good practise.

(CMS-23076)

Replaced deprecated dependency "request" with "axios"

The frontend tooling for uploading themes has been modernized. The old and deprecated dependency request has been replaced with axios. The usage of the theme-importer hasn't changed.

(CMS-22661)