Feature/debug info pass

[andrealinux1]

Add a pass which which invokes DebugHelper in order to decorate an LLVM IR module with the debug information that can be later exploited by gdb in order to perform src stepping when executing a translated binary.

Add also an option in revng translate to automatically schedule the pass.

I also addressed some doubts expressed in a previous MR that later dropped this functionality, here and here, specifically the extraction of the class definition in an header, and the addition of a cl::opt that enables to specify a name for the newly created module, while the default behavior is to overwrite the input module in place.

[aleclearmind]

Please don't stack PRs if not strictly necessary.

[PythonSHA]

@antoniofrighetto