Rename common report formatter to security report formatter for DAST

We are moving our terminology to the Security Report Format based on this repo, https://gitlab.com/gitlab-org/security-products/security-report-schemas/.

Accordingly we should use the term security_report instead of common_report.

Rename this class https://gitlab.com/gitlab-org/security-products/dast/-/blob/master/src/report/common_report_formatter.py to security_report_formatter