www/grafana7: Deprecate
- 7.x branch is deprecated upstream
- Has unfixed vulnerabilities
- grafana8 and grafana9 are available as replacements
- no consumers of grafana7 in the ports tree
PR: 266535
Reported by: drtr0jan@yandex.ru
Approved by: robsonmantovani@gmail.com (maintainer, timeout > 2 weeks)