This is the first step at separating the pacman message catalog and the
scripts message catalog. Makefiles, configure.ac, and other such files
are adjusted accordingly, as well as renaming files. The TEXTDOMAIN of
scripts is also adjusted.

Note that no actual pot or po files get changed here; these will get
pruned in a future commit so each catalog contains only the necessary
messages.

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