Restore --build command line option

Releases of sos prior to 3.0 included the '--build' option to
disable creation of a compressed archive and to leave the
temporary build tree in place. This was removed with the
reorganisation of the archive classes to support in-line
archiving. Since all supported policies are now using an archive
that derives from FileCacheArchive (commit 0178d5f) the option
can be re-introduced.

Archive classes that do not accumulate files in a temporary
directory will return the path to the in-progress archive file.

Signed-off-by: Bryn M. Reeves <bmr@redhat.com>
Fix foreman and katello for sos-3.x

The foreman and katello plug-ins committed in 4650d3f use the
sos-2.2 APIs and class names. This breaks sos since the plug-ins
will not load under 3.0.

Fix up the modules to use the new names and API conventions and
ensure that they load correctly.

Signed-off-by: Bryn M. Reeves <bmr@redhat.com>