Make browser options and capabilities configurable

[csvtuda]

This PR allows users to configure browser options and capabilities inside the qtaf.json. This was achieved through the following changes:

• hardcoded assumptions such as headless in remote drivers were removed
  • headless configurations must now take place inside the qtaf.json:

    {
    "driver": {
    "name": "chrome-remote",
    "options": [
      "--headless",
      "--disable-gpu",
      "--ignore-certificate-errors",
      "--disable-extensions",
      "--no-sandbox",
      "--disable-dev-shm-usage"
    ]
    }
    }

• existing required configurations such as the Android capabilities are now merged with the parsed ones (but should probably also be refactored/removed in the future)

The specific Android driver classes were merged into a single AndroidDriver class. Different drivers can now be created by adding the following entries in the qtaf.json:

• Chrome:

  {
  "driver": {
    "capabilities": {
      "browserName": "Chrome"
    }
  }
  }

• Firefox:

  {
  "driver": {
    "capabilities": {
      "browserName": "Firefox"
    }
  }
  }

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This should also fix #221.

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Documentation: https://github.com/Qytera-Gmbh/Qytera-Gmbh.github.io/pull/47