When the Ceph dashboard is deployed using tls everywhere, ceph-ansible
requires the dashboard_protocol variable set to 'https' to avoid the
cert/key related tasks getting skipped.
This change just adds the required variable, setting its value to 'https'
when the condition is met.
Closes-Bug: 1888982
Change-Id: Ice0ca431fe45fb20e1398dc9581bdffbd1a88f4f
7ff794663b