Add missing taskflow section

The 'taskflow' section was missing from the masakari config file *1.
Without this notification details cannot be retrieved. The 'taskflow'
section was introduced in stein *2

Adding the taskflow section causes masakari db sync to initialize new
tables which have exposed a missing dep on sqlalchemy-utils (Bug 1882900). So
until that is fixed ensure sqlalchemy-utils is installed too.

*1 https://docs.openstack.org/masakari/latest/configuration/sample_config.html
*2 https://docs.openstack.org/releasenotes/masakari/stein.html#new-features

Change-Id: I850b9978d879cecbcfd2b03491779d31c676b235
Closes-Bug: #1882656
(cherry picked from commit f051c76cf3)

src/lib/charm/openstack/masakari.py

@@ -86,3 +86,8 @@ class MasakariCharmUssuri(MasakariCharm):
 
     release = 'ussuri'
     python_version = 3
+
+    # Explicitly adding python3-sqlalchemy-utils until Bug 1882900 is fixed.
+
+    packages = ['masakari-api', 'masakari-engine', 'python-apt',
+                'python3-sqlalchemy-utils']

src/templates/stein/masakari.conf

@@ -0,0 +1,46 @@
+[DEFAULT]
+enabled_apis = masakari_api
+debug = {{ options.debug }}
+auth_strategy = keystone
+notification_driver=taskflow_driver
+
+{% if amqp.password -%}
+transport_url = rabbit://masakari:{{ amqp.password }}@{{ amqp.host }}:5672/masakari
+{% endif -%}
+
+os_user_domain_name = {{ identity_service.service_domain }}
+os_project_domain_name = {{ identity_service.service_domain }}
+nova_catalog_admin_info = compute:nova:publicURL
+os_privileged_user_name = {{ identity_service.service_username }}
+os_privileged_user_password = {{ identity_service.service_password }}
+os_privileged_user_tenant = services
+os_privileged_user_auth_url = {{ identity_service.service_protocol }}://{{ identity_service.service_host }}:{{ identity_service.service_port }}/v3
+
+wait_period_after_service_update = {{ options.evacuation_delay }}
+
+[wsgi]
+# The paste configuration file path
+api_paste_config = /etc/masakari/api-paste.ini
+
+{% if shared_db.host -%}
+[taskflow]
+connection = {{ shared_db.uri }}
+
+{% endif -%}
+
+{% include "parts/section-keystone-authtoken" %}
+
+#[keystone_authtoken]
+#www_authenticate_uri = http://10.5.0.3:5000
+#auth_url = http://10.5.0.3:35357
+#auth_type = password
+#project_domain_id = 4e1fd508dda14c6685cf980aee1f00de
+#user_domain_id = 4e1fd508dda14c6685cf980aee1f00de
+#project_name = services
+#username = masakari
+#password = KrNmPMyyVFgRdr3xYBgTgHkjBKcc8pN9rP8gxXzbKJzKZ2VR83rkfVnwtncwLmFy
+
+{% include "parts/section-database" %}
+
+[host_failure]
+evacuate_all_instances = {{ options.evacuate_all_instances }}