Implement a SAST_INCLUDED_PATH variable

Proposal

Today the SAST_EXCLUDED_PATH variable is available to exclude certain directories and files from the scope of the SAST scanner.

In case of a monorepo project, users want to only scan the directory where a change is taking place. This avoids an unnecessary long running job. Having the ability to specify which directory should be scanned specifically would be helpful when configuring the job execution.

The variable ANALYZER_TARGET_DIR exists but is not officially documented as a predefined variable. It also has the downside of showing only the relative path to the directory and not the full path in the Vulnerability Page. Therefore the link to the vulnerability in the code base is incorrect (broken link).