Clean up plug-in naming and set plugin_name for all plugin classes

Clean up some plug-ins with non-conforming or undescriptive names,
set plugin_name in all base plug-in classes to avoid <dist><plug>
names appearing in reports and remove the obsolete amd plug-in.
Rename several plug-ins:

 - rhn   -> satellite (also spacewalk)
 - i18n  -> internationalization
 - qpidd -> qpid
 - ftp   -> vsftpd

Enforce pep8 style class names for all plug-in classes.

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