build: Upgrade to Node 20

Regenerated package-lock.json with node v20 and NPM 10.
Added .nvmrc with node v20
Removed static Node.js version matrix from ci workflow switched to dynamically set the Node.js version from .nvmrc.
Added lockfile version check workflow

Second step in the Node 20 upgrade process, See the tracking issue for further information.

openedx / cypress-e2e-tests