Pytest-helm-charts

- add support for Catalog CR from Giant Swarm App Platform
- mark AppCatalog CR related functions and classes as deprecated

- fix docstring formatting
- make `get_app_catalog_object` function public

- added: a couple of extracted helper methods to use outside of `pytest`'s fixture mechanism:
- `create_app`
- `delete_app`
- `wait_for_app_to_be_deleted`
- unified imports to absolute paths

- fix: `wait_for_deployments_to_run` needs to check for `availablePods` as well
- added: `namespace_factory` fixture you can use to create test time only namespaces
- change: `app_factory` takes now one more kwarg `deployment_namespace`, which configures
the target deployment namespace for the created App CR; in other words, the `namespace` where the App
CR is created can be now different than the `deployment_namespace` where app's components are deployed
- change: if the namespace passed as `namespace` argument to `app_factory` doesn't exist, it is automatically
created using the new `namespace_factory` fixture

- fix: work-around a bug in a depended lib that was making `wait_for_deployments_to_run` fail

- change: `app_factory_func` now checks if the passed App deploys successfully. This is configured using
the `timeout_sec` argument, which by default is equal 60. Use value 0 to disable checking if App deploys OK.
- added:
- `wait_for_apps_to_run` helper method
- `wait_for_daemon_sets_to_run` helper method
- `kubectl` method in `kube_cluster`, which allows you to make any calls using the binary `kubectl`
- `random_namespace` fixture that creates a temporary namespace with a random name