docs: Add missing distros to dev guide
docs: Add missing distros to dev guide

Added references to instal guides for CentOS, SLES, and Clear Linux.

Also changed wording slightly given that some install guides (CentOS and
SLES) install some components from source.

Signed-off-by: James O. D. Hunt <348fbaadfbada55ea105602bf5609e23ac1c4898@intel.com>

chavafg/runtime,devimc/runtime,clearcontainers/runtime,devimc/runtime,chavafg/runtime,clearcontainers/runtime