Add caller info to log messages

What does this MR do?

Add caller info to show the caller of emitted log messages when using SECURE_LOG_LEVEL=debug.

Context:

• originally started as a way to help support debug a customer issue
• it's often useful to have the spot from where log msg was emitted
• gemnasium MR which uses the branch version of this MR: gemnasium!295 (closed)
• tests/go-modules job output when using gemnasium image above: https://gitlab.com/gitlab-org/security-products/tests/go-modules/-/jobs/2346888128

What are the relevant issue numbers?

Does this MR meet the acceptance criteria?

• Changelog entry added
• Documentation created/updated for GitLab EE, if necessary
• Documentation created/updated for this project, if necessary
• Documentation reviewed by technical writer or follow-up review issue created
• Tests added for this feature/bug
• Job definition updated, if necessary
  • Auto-DevOps template
  • Job definition example
  • CI Templates
• Conforms to the code review guidelines
• Conforms to the Go guidelines
• Security reports checked/validated by reviewer