Add legion host identifier

[balag0]

Subsequent PRs will customize different host services as required. Scope of this PR is to add a way to check if container is running on a Legion host.

[### Issue describing the changes in this PR] https://github.com/Azure/azure-functions-host/issues/8616

resolves #issue_for_this_pr

Pull request checklist

• [X ] My changes do not require documentation changes
  • [ ] Otherwise: Documentation issue linked to PR
• [ X] My changes should not be added to the release notes for the next release
  • [ ] Otherwise: I've added my notes to release_notes.md
• [ ] My changes do not need to be backported to a previous version
  • [X ] Otherwise: Backport tracked by issue/PR https://github.com/Azure/azure-functions-host/issues/8616
• [ X] My changes do not require diagnostic events changes
  • Otherwise: I have added/updated all related diagnostic events and their documentation (Documentation issue linked to PR)
• [ ] I have added all required tests (Unit tests, E2E tests)