wrong use of a f-string when no variable is templated

Signed-off-by: Sven Kieske <kieske@osism.tech>
Change-Id: I4ef5147eacef32ed93c21d44bf23b664adf1eb91

Implements: Kolla Ansible
Closes-Bug: #2043554
Change-Id: I5648a79b4aa1960f1984a5179e3dfc3f0982c709

Kolla environment currently uses haproxy
to fullfill HA in mariadb. This patch
is switching haproxy to proxysql if enabled.

This patch is also replacing mariadb's user
'haproxy' with user 'monitor'. This replacement
has two reasons:
  - Use better name to "monitor" galera claster
    as there are two services using this user
    (HAProxy, ProxySQL)
  - Set password for monitor user as it's
    always better to use password then not use.
    Previous haproxy user didn't use password
    as it was historically not possible with
    haproxy and mariadb-clustercheck wasn't
    implemented.

Depends-On: https://review.opendev.org/c/openstack/kolla/+/769385
Depends-On: https://review.opendev.org/c/openstack/kolla/+/765781
Depends-On: https://review.opendev.org/c/openstack/kolla/+/850656

Change-Id: I0edae33d982c2e3f3b5f34b3d5ad07a431162844