Documentation: capabilities: focus on runtime configuration
Documentation: capabilities: focus on runtime configuration

Reorder capabilities docs to focus on how to configure them at runtime.

coreos/rkt,joshix/rkt,coreos/rkt,lucasallan/rkt,lucasallan/rkt,coreos/rkt,kinvolk/rkt,joshix/rkt,rkt/rkt,kinvolk/rkt,joshix/rkt,alban/rkt,kinvolk/rkt,lucasallan/rkt,rkt/rkt,kinvolk/rkt,lucasallan/rkt,joshix/rkt,alban/rkt,alban/rkt,rkt/rkt,rkt/rkt