Description of problem:

The backstage CRD doesn't allow a user to mount a configMap (and probably a secret too) if the resource name contains a `.` : `[spec.template.spec.volumes[4].name: Invalid value: \"kube-root-ca.crt\": must not contain dots`.

Prerequisites (if any, like setup, operators/versions):

RDHD 1.1.2.

Steps to Reproduce

Adding the following configuration to the CRD is an easy way to reproduce the issue:
```
spec:
application:
extraFiles:
configMaps:

• name: kube-root-ca.crt
  mountPath: /ingress-cert
  ```

Actual results:

Backstage UI is not deployed.

Expected results:

Resource name is sanitized and the Backstage UI is deployed.

Reproducibility (Always/Intermittent/Only Once):

Always

Build Details:

Additional info (Such as Logs, Screenshots, etc):