refactor and improve tests

[zdaratom-s1]

• speedup tests, remove redundant steps and unused code
• improve readability
• rename methods
• improve logging
• improve asserts (verify splunk alert results in DataSet)

[zdaratom-s1]

Note that if the application fails to deploy test will fail no matter if you go via url or clicking through menu. Clicking through menu is imho just slower.

I understand that actions approach, on the other hand such a steps are bit more complicated to use since you need to keep context in test. I have found idempotent steps be more convenient and reusable.

[martin-majlis-s1]

When I check the current run: https://github.com/scalyr/dataset-addon-for-splunk/actions/runs/5975394444/job/16211261116?pr=74

  Slow test file: [chromium] › alert_action.spec.ts (3.0m)
  Slow test file: [chromium] › inputs.spec.ts (43.1s)
  Slow test file: [chromium] › examples.spec.ts (27.0s)
  Slow test file: [chromium] › search.spec.ts (20.6s)

With some previous run: https://github.com/scalyr/dataset-addon-for-splunk/actions/runs/5964013188/job/16178341279

  Slow test file: [chromium] › inputs.spec.ts (1.1m)
  Slow test file: [chromium] › search.spec.ts (42.1s)
  Slow test file: [chromium] › alert_action.spec.ts (31.3s)
  Slow test file: [chromium] › examples.spec.ts (23.6s)
  Slow test file: [setup] › global.setup.ts (15.4s)

The only speed up is as expected on the inputs/search since there are multiple tests. I agree, that it's fine to use url to get somewhere, but there should be at least one test for the navigation, to make sure, that it works.

[zdaratom-s1]

I have added new test verifying that add on is deployed properly (asserting link and menu items)