Bug fix: don't constantly update APIRule in tests while getting the status

[mluk-sap]

Description

Changes proposed in this pull request:

• Refactored the way of applying apiRules in tests, so the behavior is more explicit and predictable:
  • introduced a function to read single manifest template from yaml file (returns error if there are multiple manifests)
  • simplified APIRule helper functions, so they do what is expected:
    • applyApiRule creates new single ApiRule (returns error if APIRule exists)
    • updateApiRule updates an existing single ApiRule (returns error if APIRule doesn't exist)
    • these functions don't call UpdateResources anymore in order to get APIRule status, which was breaking tests a lot
  • istio-jwt / scenario_noauth_and_jwt - proper installation of two APIRules (previously only one was considered in state analysis)
  • ory / service_per_path - helloworld workload deployed explicitly (previously it was deployed as a side effect of applying APIRule)
• Reintroduced ScenarioInitializer for all tests, which improves test separation (regenerates random identifiers) and allows to detect cases where tests share some state in an implicit way (previously Custom Domain tests were sharing the same APIRule name)
• Refactored Custom Domain tests (because of ScenarioInitializer changes):
  • custom domain resources are prepared in BeforeSuiteHooks and cleaned in AfterSuiteHooks
  • scenarios are now separated, so they don't share any state, which is a good practice (previously APIRule was common)
  • improved readability of logs - more logs during preparation, test output is not convoluted by log messages, etc.
  • renamed some variables, so their purpose is more clear (like subdomainForTests)
• Improved APIRule related error messages, so they contain more context information (like APIRule name)

Pre-Merge Checklist

• As a PR reviewer, verify code coverage and evaluate if it is acceptable.

Related issues

[Ressetkk]

lgtm. Thanks.