Feature request or enhancement

For feature requests or enhancements, provide this information, please:

Which use case/requirement will be addressed by the proposed feature?

I'm working on building minimal image size and features for connect, something we could call connect-slim for now my images are based on connect-base but to improve it a little bit more I'll need to based images on the superior level kafka from connect-base Dockerfile to connect Dockerfile 

Implementation ideas (optional)

I suggest to move all the command RUN docker-maven-download from connect-base to connect  as is anyone will be able to build images with only the needed feature

If you think that is a good idea I can prepare the pull request on my own

Thanks for all the work you do on this amazing tool