[Enhancement] Streamline DAB Validate output to JUnit XML File Format

Improve the output of the `dab validate` command instead of console logs.
For example, if you have three configurations, the final output should include a summary:

dab-config.json is Valid
dab-config-2.json is Valid
dab-config-3.json is Valid

This issue would entail returning an output to improve the `dab validate -o` command to include a formatter which would define the output - JUnit XML file format which is conformant with CI/CD pipelines just like Unit Tests output structured reports.