Add junit compatible reports

[man1207]

Hi!
Here is junit report feature.

1. Enable feature by passing --junit-xml as cmd-line param or put junit: yes into global config file
2. Report will be generated and saved into logs/latest/report.xml
3. Then you are allowed to pass report next into reporter action in tests workflow to print out test results summarized or detailed.
4. Excluded tasks (when you exclude or include ones in global config) will be displayed like skipped in report as well

Here is an example of how it can be displayed in run summary
https://github.com/man1207/SIPssert/actions/runs/12482574669/attempts/1#summary-34836934692
or in detailed
https://github.com/man1207/SIPssert/actions/runs/12482574669/job/34837079496

I don't include here commits related to actions/workflows. Only feature code.
If you wish to modify action and workflow to gain junit reports in SIPssert repo it can be performed such a way:

1. Add --junit-xml cmd-line param when execute sipssert command in action.
2. Or put junit: yes into global config file in sipssert-opensips-tests repository
3. Next take report and pass into action that displays report in run summary (mikepenz/action-junit-reportor dorny/test-reporter for instance). You can call these actions from sipssert-opensips-tests repo by calling mikepenz/action-junit-report per job and dorny/test-reporter for run as a whole (you must aggregate reports from artifacts in such case).

Or, if you wish, I can bring commits that generate reports in workflow run in yet another PR. Look at links above. Do you like how reports look in workflow run?