add helmStringValues support

[faust2199]

Fixes #1179

[gerardcl]

LGTM! 🚀

[jafarre-bi]

Do we need both values and string values? We are using strings in both cases. Not sure about its usefulness.
Apart from that, this is a new parameter that we need to reflect in the TIR. The changes to the TIR are about to be merged. When that is ready, merge those changes into this branch and add the support for this new parameter.

[jafarre-bi]

Please wait for the changes to the TIR which are about to be merged and then update the TIR with this new parameter.

[faust2199]

Do we need both values and string values? We are using strings in both cases. Not sure about its usefulness. Apart from that, this is a new parameter that we need to reflect in the TIR. The changes to the TIR are about to be merged. When that is ready, merge those changes into this branch and add the support for this new parameter.

It is possible that someone has been using existing automatic type conversion. A hypothetical example:

  odsComponentStageRolloutOpenShiftDeployment(context, [
    'selector': "app.kubernetes.io/name=${context.componentId}",
    'helmEnvBasedValuesFiles': ["values.env.yaml"],
    'helmValues': [
      'replicaCount': '3',
    ],
  ])

The above works, because it becomes --set replicaCount=3, then 3 becomes integer. If we make it always --set-string, then it will not work. Of course, it is also possible that no one has been using it this way and we don't have to maintain backwards compatibility.