WIP: Copy to work directory if defined

What does this MR do?

Copy project directory to container's working dir when copy mode is enabled and working directory is properly set.

Why was this MR needed?

We can't copy to a pre-defined directory like /tmp/app since the container may not be able to create files in this directory.

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• Tests added for this feature/bug

What are the relevant issue numbers?

https://gitlab.com/gitlab-org/security-products/analyzers/find-sec-bugs-gradle/issues/2