Semgrep - Prevent from calling semgrep servers and use our stable rules by default

[fproulx-boostsecurity]

• Updated semgrep to latest version (for Semgrep Pro also)
• Added POSIX-compliant rule validation logic to assert that auto or equivalent (p/python, etc.) is not used
• Disabled semgrep metrics, which hard crashes if the validation logic would get bypassed somehow
• Point to new default stable Boost curated rules set hosted on our assets CDN on S3
• Smoke tests with attempt to use auto (should fail)
• Smoke tests default value
• Tested on GitHub Actions
• Tested on Gitlab (can be done once we merged this PR to dev registry)
• @guilbocz-boost validated that no customer used custom rules (except one, which uses Semgrep Pro with their license) - https://docs.google.com/spreadsheets/d/1TfPvkVdUkndf6ZAZUyy96lj32kSOa80Q3vr4Uy_-Sw4/edit?gid=0#gid=0

Smoke test with SEMGREP_RULES with auto
https://github.com/boost-sandbox/module-tests-semgrep/actions/runs/14088810008/job/39459926581#step:3:48

Smoke test with new default value
https://github.com/boost-sandbox/module-tests-semgrep/actions/runs/14088861659/job/39460109580#step:3:58