Fix arg names for dhcp pool crete, update docs

[kgawda]

Fix the command line arguments definition for "dhcp-pool create". It was missing some commas in the code. Thanks to this fix, eg.: -g and --gateway-ip are separate options, instead of -g--gateway-ip. Also re-generated docs to reflect changes. I used the script present in repo (generate-docs.py). This is why so many docs files are changed.

[kgawda]

I just discovered it fixes issue #532