SAST support for C and C++: Beta release
## Summary
While addressing [feedback](https://gitlab.com/gitlab-org/gitlab/-/issues/550276) on the experimental release of the [`clangsa` analyzer](https://gitlab.com/gitlab-org/security-products/analyzers/clangsa#) we will simplify configuration, improve performance, and enable optional cross-file scanning.
### Lift the analysis to the pipeline
The design goal of this epic is to split the analysis job into parts that can be easily recombined in useful ways with pipeline configuration.
The primary benefits are
- intuitive scaling of analysis compute power
- better visibility into the scan
- lower-risk, faster updates (from decoupling)
This design also supports adaptive analysis, where the analyzer is configured using a fast preliminary scan of the target project. "Configuration" may range from tweaking parameters to wholesale choice of a different analyzer.
For the beta release our aim is only to log suggested configuration changes. As we gain confidence, we'll automate configuration changes.
epic