Create utility class for compareXml/compareTxt

[miovd]

• Do you want to request a feature or report a bug? Refactoring

• What is the current behavior? Utility classes compareXml and compareTxt are in AbstractConverterTest

• What is the expected behavior? These methods should be in a utility class ComparisonUtils

• What is the motivation / use case for changing the behavior? Cleaner design

• Please tell us about your environment:

  • PowSyBl Version: 4.10.0-SNAPSHOT

[sfid98]

Hi @miovd, I have worked to this issue in this PR: #2209 Please take a look, this is my first contribution and I hope that the changes are good Thank you