[megacli] add new command and switch to add_copy_specs

Signed-off-by: Bryn M. Reeves <bmr@redhat.com>
[sosreport,archive] fix command line compression method selection

Signed-off-by: Bryn M. Reeves <bmr@redhat.com>
[docs] document -z, --compression-type in sosreport(1)

Signed-off-by: Bryn M. Reeves <bmr@redhat.com>
[general] delete UbuntuGeneral and incorporate into General

The UbuntuGeneral plugin just collects '/etc/os-release' which is
not specific to Ubuntu distributions. Move it to the General class
itself and delete the child class.

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