Migrate common/v2/issue to report package structs

What does this MR do?

Migrate common/v2/issue to report package structs

Populates project with all existing code from common subpackage with the following differences:

• Rename package issue to report
• Rely on analyzers/ruleset over common/v2/ruleset
• Simplify TestDisableIdentifierReports spec to rely on fewer fixtures
• Add README, CHANGELOG, LICENSE, and CONTRIBUTING
• Fix gosec issues with dd9c126c

What are the relevant issue numbers?

• gitlab-org/gitlab#211819 (closed)
• gitlab-org/gitlab#8398 (closed)

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