commitpkg: rework for new community layout

Remove the community-specific code that calls tupkg. Make the server
variable a bit more dependent on what repo we are uploading to in order to
get community working, and finally create the correct symlinks for
communitypkg in the Makefile.

Note that this change will require the Arch devtools package to get a
replace entry for aurtools.

Signed-off-by: Dan McGee <dan@archlinux.org>