Add rke2-test-values.yaml to pipeline

Closes https://repo1.dso.mil/platform-one/big-bang/bigbang/-/issues/927

Summary of this MR:

• Added a $CI_VALUES_OVERRIDES_FILE variable to the aws/rke2/bigbang up job in pipelines/bigbang.yaml to specify a values file that is specific to RKE2 pipeline runs

  • https://repo1.dso.mil/platform-one/big-bang/pipeline-templates/pipeline-templates/-/blob/rke2-test-values/pipelines/bigbang.yaml#L332

• Added a conditional check in scripts/deploy/deploy/01_deploy_bigbang.sh that checks if the $CI_VALUES_OVERRIDES_FILE variable is set

  • https://repo1.dso.mil/platform-one/big-bang/pipeline-templates/pipeline-templates/-/blob/rke2-test-values/scripts/deploy/01_deploy_bigbang.sh#L49

  • If it is, then deploy bigbang with the values file (in this case, tests/rke2-test-values.yaml) specified in the $CI_VALUES_OVERRIDES_FILE variable along with the baseline values file test/test-values.yaml

  • If it is not, then deploy bigbang with the baseline values file test/test-values.yaml only