As described in https://github.com/openstack-k8s-operators/test-operator/pull/200, we historically have the ExtraMounts interface that can be use to define the same set of information for ConfigMaps, Secrets, and any other k8s supported object that can be mount within a Pod (see [1] as an example).
The goal of this jira is to include the storage module from lib-common [2] and
make the implementation consistent to what has been done for the other operators.
Here some documentation [3] and here a very basic implementation (that is what is needed here [4]) that we did for horizon.

DoD:

• Test operator uses ExtraMounts instead of ExtraConfigmapsMounts with the implementation that is consistent with the rest of the operators.

[1] openstack-k8s-operators/cinder-operator#65
[2] https://github.com/openstack-k8s-operators/lib-common/tree/main/modules/storage
[3] https://github.com/openstack-k8s-operators/dev-docs/blob/main/extra_mounts.md
[4] openstack-k8s-operators/horizon-operator#308