Adds zsh completion

Use nova bash-completion to add native zsh completion using built in
parameter expansion.  Nothing spectacular or new, this is mostly so that
zsh users do not need to autoload bashcompinit just to use nova.

Change-Id: I56f62f036e0c85e79197f4c7dfd25abf7eb4110a
Implements: zsh completion
Clean up and make HACKING.rst point to openstack-dev/hacking

Instead of having a full local copy of HACKING Reference the OpenStack
hacking guide (openstack-dev/hacking) and remove duplicate sections.

Change-Id: Iaabc27c42d74b7441c17e63db15724f64114620b
Remove uncessary code related to nova start/stop

'nova start' and 'nova stop' actually send request with 'os-start'
and 'os-stop', instead of 'start' and 'stop'.

Change-Id: I1472e1b648dae8f3b281a113adb60421a00e5a48
Add AgregatesManager.get()

utils.find_resource() uses manager.get() as part of converting Resource
names to IDs.  AggregatesManager had get_details() instead of get().

Add AggregatesManager.get(), leaving .get_details() in place for backward
API compatibility.

Bug: 1200341

Change-Id: I7d238bbe43e1760e31f1a9ba783c668246f20844
Merge "Adds zsh completion"
Merge "Remove uncessary code related to nova start/stop"
Merge "Clean up and make HACKING.rst point to openstack-dev/hacking"
Merge "Add AgregatesManager.get()"