Add basic smoke test for config changes

[UnicornChance]

New Feature

Need to add a/some basic smoke tests for making changes to the config so that it doesn't just break uds-core when it gets there.

Describe the solution you'd like

A generic build of identity-config image and use that image to successfully deploy keycloak.

Create task for building uds-core and then testing the new image with keycloak, update docs as well to represent that new task and how to use it.

Additional Background Info

Further e2e/integration tests are not captured in this and will be implemented in uds-core repo.

[rjferguson21]

I think a good option might be to test against the updated core-istio bundle that includes keycloak - defenseunicorns/uds-core#262

I've been testing using this zarf.yaml

kind: ZarfPackageConfig
metadata:
  name: identity-config
  description: Identity Config

components:
  - name: identity-config
    required: true
    actions:
      onDeploy:
        after:
          - cmd: |
              kubectl set image sts/keycloak uds-config=uds-core-config:keycloak --namespace=keycloak
    images:
      - uds-core-config:keycloak

with this task (includes full uds-core which is probably not appropriate for CI in the uds-identity-config repo):

  - name: uds-core-integration-test
   description: "UDS Core integration test"
   actions:
     - cmd: uds deploy ghcr.io/defenseunicorns/packages/uds/bundles/k3d-core-demo:0.15.1 --confirm
     - task: dev-build
     - cmd: uds zarf package create . --confirm && uds zarf package deploy zarf-package-identity-* --confirm