Watcher official install-guide

Currently watcher project does not have an official
install guide at [1]

This patch adds watcher install guide for rdo and debian.

install-guide is written following the document [2].

[1] https://docs.openstack.org/project-install-guide/ocata/
[2] https://docs.openstack.org/contributor-guide/project-install-guide.html

Change-Id: Idfae7286003f81222dadf91ddcaf95a42c7eb07f

install-guide/source/common_configure.rst

@@ -0,0 +1,71 @@
+2. Edit the ``/etc/watcher/watcher.conf`` file and complete the following
+   actions:
+
+   * In the ``[database]`` section, configure database access:
+
+     .. code-block:: ini
+
+        [database]
+        ...
+        connection = mysql+pymysql://watcher:WATCHER_DBPASS@controller/watcher?charset=utf8
+
+   * In the `[DEFAULT]` section, configure the transport url for RabbitMQ message broker.
+
+     .. code-block:: ini
+
+        [DEFAULT]
+        ...
+        control_exchange = watcher
+        transport_url = rabbit://openstack:RABBIT_PASS@controller
+
+     Replace the RABBIT_PASS with the password you chose for OpenStack user in RabbitMQ.
+
+   * In the `[keystone_authtoken]` section, configure Identity service access.
+
+     .. code-block:: ini
+
+        [keystone_authtoken]
+        ...
+        auth_uri = http://controller:5000
+        auth_url = http://controller:35357
+        memcached_servers = controller:11211
+        auth_type = password
+        project_domain_name = default
+        user_domain_name = default
+        project_name = service
+        username = watcher
+        password = WATCHER_PASS
+
+     Replace WATCHER_PASS with the password you chose for the watcher user in the Identity service.
+
+   * Watcher interacts with other OpenStack projects via project clients, in order to instantiate these
+     clients, Watcher requests new session from Identity service. In the `[watcher_client_auth]` section,
+     configure the identity service access to interact with other OpenStack project clients.
+
+     .. code-block:: ini
+
+        [watcher_client_auth]
+        ...
+        auth_type = password
+        auth_url = http://controller:35357
+        username = watcher
+        password = WATCHER_PASS
+        project_domain_name = default
+        user_domain_name = default
+        project_name = service
+
+     Replace WATCHER_PASS with the password you chose for the watcher user in the Identity service.
+
+   * In the `[oslo_messaging_notifications]` section, configure the messaging driver.
+
+     .. code-block:: ini
+
+        [oslo_messaging_notifications]
+        ...
+        driver = messagingv2
+
+3. Populate watcher database:
+
+   .. code-block:: ini
+
+     su -s /bin/sh -c "watcher-db-manage" watcher