Add generic label to identify objects created by Stackable #188
Description
See follow-up issue: #503
Currently we do not have a way of identifying all Stackable objects that were created in the api-server.
We should add a single label with a known value like "vendor=stackable" or something similar that would allow easily auditing the objects created across our entire plattform.
### Prerequisites
- [ ] https://github.com/stackabletech/documentation/pull/443
- [ ] https://github.com/stackabletech/operator-rs/pull/684
- [ ] https://github.com/stackabletech/stackable-cockpit/pull/134
- [ ] https://github.com/stackabletech/operator-rs/pull/723
- [ ] https://github.com/stackabletech/operator-rs/pull/734
### Label Templated files
- [ ] https://github.com/stackabletech/issues/issues/501
- [ ] https://github.com/stackabletech/demos/pull/9
- [ ] https://github.com/stackabletech/issues/issues/513
stackablectl will not support handing over a values.yml to Helm. if you want one, use Helm.
### Label resources deployed by the operators
- [ ] https://github.com/stackabletech/operator-rs/pull/728
- [ ] Bump `operator-rs` in operators to get the vendor label (optional, will happen anyway)
### Docs
- [ ] https://github.com/stackabletech/documentation/pull/540
- [ ] https://github.com/stackabletech/documentation/pull/542