[Proposal] Use heredoc instead of escape character '/' and operator '&&' in Dockerfile RUN instruction

[swivelmargarita]

I believe using heredoc in Dockerfiles (as mentioned in docker docs here) would increase readability overall. I didn't make sure the formatting, indentation etc. were correct, just modified the file so that it would work identical to old Dockerfile with '/'s and '&&'s.
If there are problems with the file let me know.

Thanks, Takha

[swivelmargarita]

I created a pull request: #187