Iac-test

- Add dry-run option
- Make Robot include and exclude tags available in render process (`robot_include_tags` and `robot_exclude_tags` variables)

- Also copy non-robot files to temporary directory used for executing the tests

- Handle file errors gracefully
- Allow empty YAML files

- Do not merge YAML dictionary list items, where each list item has unique attributes with primitive values

- Fix issue with YAML attributes named `tag`
- Fix multiple instances of `include` and `exclude` CLI arguments

- Add support for ansible-vault encrypted values
- Add `!env` tag to read values from environment variables