Add codeql workflow

[n0y0nD]

This PR adds a CodeQL advanced workflow for the pappl-retrofit repository to enable automated security analysis.
The workflow runs on each push and pull request targeting the master branch, and performs static analysis for C/C++ code using GitHub CodeQL.
It includes:
∙ CodeQL initialization and analysis setup
∙ Build steps using ./configure and make
∙ Required dependencies: libcups2-dev, libppd-dev (via apt) and PAPPL v1.4.10 (built from source, pinned to v1.x for API compatibility)
This improves code quality and helps detect potential security vulnerabilities early in the development process.

[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.