Add Info file to distribution

[DSMasterson]

I much prefer having the package documentation for a package readily available on my system -- that's what Info is for. The README.org seems to export to texi and info without a problem. All that seems to be needed is add a couple of commands to the Makefile to generate the info and dir file and make sure they're handled by (M?)ELPA properly.

I see that your Makefile seems geared toward Mac (docker) which I don't use. If you have the "info" and "texinfo" system packages installed (probably use 'apt install'), then the commands to generate the info and dir files would be:

emacs --batch -q -l org -l ox-texinfo --eval '(progn (find-file "README.org") (org-texinfo-export))'
install-info README.info dir