Create convenience deploy step to copy over a few files

In some (Most? All except QBS?) of the currently supported build systems it's difficult, if not impossible, to specify all required-to-be-deployed files within the build system.

While it is possible to handle such extra deployment using a Custom Process Step in the deploy configuration running scp or similar, this is clumsy for the typical case "here are a few files that I want to end up there".

Would be nice to have something less clumsy for that use case.