ci: Enable Semgrep and Zizmor scans

[adimoft]

This pull request adds two new GitHub Actions workflows to enhance security scanning in the repository. The workflows integrate Semgrep and Zizmor, both popular static analysis tools, into the CI pipeline. Each workflow includes steps for hardening the runner, checking out code, running the respective scan, and handling scan results.

Jira: https://jira.devtools.intel.com/browse/NEXUIE-132281

Security scanning integration:

• Added .github/workflows/semgrep.yml to run Semgrep scans on pushes and pull requests to main, using a containerized Semgrep image and a reusable action for scan execution. The workflow ensures runner hardening and outputs results in text format.
• Added .github/workflows/zizmor.yml to run Zizmor scans on pushes and pull requests to main, installing the scanner via the uv package manager, generating SARIF reports, uploading results to GitHub Security, and saving artifacts for later review. The workflow also includes runner hardening.

[github-advanced-security]

You are seeing this message because GitHub Code Scanning has recently been set up for this repository, or this pull request contains the workflow file for the Code Scanning tool.

What Enabling Code Scanning Means:

• The 'Security' tab will display more code scanning analysis results (e.g., for the default branch).
• Depending on your configuration and choice of analysis tool, future pull requests will be annotated with code scanning analysis results.
• You will be able to see the analysis results for the pull request's branch on this overview once the scans have completed and the checks have passed.

For more information about GitHub Code Scanning, check out the documentation.