Reorganizing guix package commands

[Alex Kost]

I've just sent a message to bug#22587¹, but I realized it is better to
discuss it here in a separate thread.

So, I think there are inconsistencies in guix commands.  For example, we
have "guix system build" to build a system, but "guix build" to build a
package.  IMO "guix package build" would be a better choice.

In general, I think it would be good to move package commands inside
"guix package", e.g, to make "guix package lint", "guix package size",
etc.

Wouldn't it be great to make some breaking changes?  I mean if this or
any other proposal on "guix" command structure is reasonable, I think
it's just the time for it while Guix is still alpha/beta.  Otherwise,
the current command structure will never be changed.

¹ http://debbugs.gnu.org/cgi/bugreport.cgi?bug=22587#29

-- 
Alex