Improve current end-to-end test coverage for kogito-tooling channels

Summary
Current coverage of kogito-tooling channels needs to be extended and improved to cover more scenarios and allow us to better prevent regressions and have higher confidence in the end product.

Goals

• Add smoke e2e smoke tests for kogito-bpmn editor (DMN part is already complete).
• Improve coverage of vscode extension and wait for editors to load before passing the test in community.
• Add automated test for VSCode extension
  • https://developers.redhat.com/blog/2019/11/18/new-tools-for-automating-end-to-end-tests-for-vs-code-extensions/
  • https://github.com/djelinek/vscode-uitests-tooling
• Add automated spectron tests for Desktop application.
• Add automated cypress tests for Online editor.

Non-goals
Create a automated test suite separated from community code.

Acceptance criteria
Issues in epic are resolved.