Because --enable-application is the current way to do things, transpose
it to configure.py, but since --enable-application=js doesn't make
sense, make it an alias of a new --enable-project option.
This only partially moves --enable-application out of old-configure.in
because there are a lot of other things intertwined with it.
This moves all the reading mozconfig, finding autoconf, refreshing the
old configure, and running the old configure into sandboxed
moz.configure. This effectively bootstraps the sandboxed python configure.
Mike Hommey