masslinter: Generate junit reports

Gitlab can parse junit reports and produce nice user-friendly outputs. Shellcheck and hadolint however, cannot generate these outputs. They can provide checkstyle outputs.

Using a simple XSLT (XML Translator) we can convert checkstyle XML to junit XML.

Further more, to keep pipeline output consistent, also add an XSLT to translate to text-output, mostly useful to pipeline outputs.

Until gitlab properly supports checkstyle or SARIF outputs (via #1), this is the best we can do for now.

Note, that two tests are expected to fail due to their failure test reports. This is expected for obvious reasons.