Implement DevStack plugin

Use DevStack's plugin model to allow for developers to easily set up
the Watcher services within DevStack.

Provides documentation on how to use the plugin as well as documentation
on how to configure a multi-node DevStack installation to use.  Also
provides an example local.conf for both the controller and compute
nodes.

Implements blueprint devstack-plugin

Change-Id: Ide663813f7a49d645877a21a0d1914be3218385e

devstack/local.conf.controller

@@ -0,0 +1,48 @@
+# Sample ``local.conf`` for controller node for Watcher development
+# NOTE: Copy this file to the root DevStack directory for it to work properly.
+
+[[local|localrc]]
+
+ADMIN_PASSWORD=nomoresecrete
+DATABASE_PASSWORD=stackdb
+RABBIT_PASSWORD=stackqueue
+SERVICE_PASSWORD=$ADMIN_PASSWORD
+SERVICE_TOKEN=azertytoken
+
+HOST_IP=192.168.42.1 # Change this to your controller node IP address
+FLAT_INTERFACE=eth0
+
+FIXED_RANGE=10.254.1.0/24 # Change this to whatever your network is
+NETWORK_GATEWAY=10.254.1.1 # Change this for your network
+
+MULTI_HOST=1
+
+# This is the controller node, so disable nova-compute
+disable_service n-cpu
+
+# Disable nova-network and use neutron instead
+disable_service n-net
+ENABLED_SERVICES+=,q-svc,q-dhcp,q-meta,q-agt,q-l3,neutron
+
+# Enable remote console access
+enable_service n-cauth
+
+# Enable the Watcher plugin
+enable_plugin watcher git://git.openstack.org/openstack/watcher
+
+# Enable the Ceilometer plugin
+enable_plugin ceilometer git://git.openstack.org/openstack/ceilometer
+
+# This is the controller node, so disable the ceilometer compute agent
+disable_service ceilometer-acompute
+
+LOGFILE=$DEST/logs/stack.sh.log
+LOGDAYS=2
+
+[[post-config|$NOVA_CONF]]
+[DEFAULT]
+compute_monitors=cpu.virt_driver
+
+[[post-config|$WATCHER_CONF]]
+[watcher_goals]
+goals=BASIC_CONSOLIDATION:basic,DUMMY:dummy