[packman] full featured chromium for SLE12 missing

[Olaf Hering]

Raymond,

there is appearently no chromium for SLE_12 in OBS or PMBS, only its
ffmpeg subpackage. This is sad, today I had an urgend need for chromium.

I think for SLED and for simplicity the packman_bs yes/no knob in the
spec file should be converted into a bcond to build the individual
subpackages. The default should be as it is done now, only the main pkg
gets build. In Essentials prjconf the ffmpeg subpackage will be enabled,
the main pkg gets disabled. And for SLE_12 both get enabled.

What do you think?

Olaf