Change default user id and gid

[lfrancke]

Description

Part of stackabletech/issues#645

Change default user id and gid to the same ones we use in the operators themselves.
These are only the defaults that are used when a Pod does not specify their own securityContext.runAsUser or runAsGroup.

As of now all our operators do set these (and fsGroup) to 1000 and 0 respectively.
As the next step we want to remove that hardcoding so the default would then fall back to what we specify here.

Therefore I do believe that this PR should be a simple change with no downstream consequences until the PRs from stackabletech/issues#651 are merged.

Definition of Done Checklist

• Changes are OpenShift compatible
• Add an entry to the CHANGELOG.md file
• Integration tests ran successfully

TIP: Running integration tests with a new product image

The image can be built and uploaded to the kind cluster with the following commands:

bake --product <product> --image-version <stackable-image-version>
kind load docker-image <image-tagged-with-the-major-version> --name=<name-of-your-test-cluster>

See the output of bake to retrieve the image tag for <image-tagged-with-the-major-version>.

[stackable-bot]

All committers have signed the CLA.

[lfrancke]

Release Notes

The default user id and group id used by all our docker images was 1000. This has now been changed to high random numbers (782252253 / 574654813 respectively). Additionally our operators also hardcoded these values. This also changed which means that the user ids and group ids will change as of this release. This is for security purposes to reduce the chance of overlaps with existing ids on the host.

[lfrancke]

This was reverted in #1115 and needs to be reapplied once Step 2 from the issue to not hardcode uid & gid in operators is finished.