[MICROBA-1743]
Fixes an issue where we couldn't override the header and footer with the branded versiom within the Comms MFE because some of the dependencies of the branded components are not currently Webpack5 compliant. Adds a rule to make webpack5 less strict with imports that do not include a file extension.
This also includes a change so that the Comms MFE uses the Open edX branded colors/styles by default.
