Rename Mistral dashboard to Workflow
Rename Mistral dashboard to Workflow

We register mistral as workflow service to keystone, so use 'Workflow'
makes more sense than 'Mistral' as a dashboard name, just like we don't
call compute dashboard 'Nova'.

Change-Id: Ia347dd8266857dc54aa542a45f2c873de4925614

openstack/mistral-dashboard,openstack/mistral-dashboard,openstack/mistral-dashboard