Add flag for rtl target to files without target - #186

What exactly is the intended way this interacts with bender script --no-default-target?

The --no-default-target removes the default targets for different script formats (e.g., simulation for vsim). The --assume-rtl target makes sure every source file from the manifests has a target, if any file does not it receives the rtl target. The arguments should not interact, as one applies to the applied targets (similar to adding a -t <TARGET> flag), one applies to the sourcefile list.