[KOGITO-9702] Fix container-builder kaniko build context to consider external resources

[ricardozanini]

TODO:

• - Finish unit tests
• - Integrate with the main operator module
• - Do integration tests to verify the new behavior

Description of the change:
In this PR, we fix a bug where the internal Kaniko builder won't consider the SonataFlow .spec.resources when building an image.

Motivation for the change:
See: https://issues.redhat.com/browse/KOGITO-9702

Checklist

• Add or Modify a unit test for your change
• Have you verified that tall the tests are passing?

How to backport a pull request to a different branch?

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NOTE: backporting is an action aiming to move a change (usually a commit) from a branch (usually the main one) to another one, which is generally referring to a still maintained release branch. Keeping it simple: it is about to move a specific change or a set of them from one branch to another.

Once the original pull request is successfully merged, the automated action will create one backporting pull request per each label (with the previous format) that has been added.

If something goes wrong, the author will be notified and at this point a manual backporting is needed.

NOTE: this automated backporting is triggered whenever a pull request on main branch is labeled or closed, but both conditions must be satisfied to get the new PR created.

[ricardozanini]

Backporting since OpenShift builds might be compromised. Since builds are not supported for TP1, we don't need to cherry-pick it.