metapackage

add a start of a metapackage to give to DSA, so they can easily keep things we
need installed.

Two things:

 - this could be splitted in a "ftpmaster-common" (meaning "that is needed at least to
   get a dak running") and "ftpmaster-$release" (meaning "all we also need before we
   do any work) package
 - This is not yet checked for completness, but its a good start.

Signed-off-by: Joerg Jaspert <joerg@debian.org>