Separate docs and lib, please

[wilbowma]

Feature request

Maybe most people don't have this issue, but everytime I re/install frog, I hesitate as I look at the dependencies (the docs in particular have pretty heavy dependencies).

The following uninstalled packages are listed as dependencies of frog:
   find-parent-dir
   html-lib
   markdown
   rackjure
   reprovide-lang
   net-doc
   racket-doc
   scribble-doc
   web-server-doc