New window: "Raw" resource editor

[dertseha]

In order to obsolete the old tool "chunkie" (and provide a better import/export functionality), add a new window, which allows to export (and possibly import) raw resources - without larger context.

It would operate on the raw media types, perhaps a preview, and only import/export buttons.
As an option, it could provide more detailed actions, such as manually creating/removing entire resources.

A further note could warn about possible side-effects. For instance, because it wouldn't know any better, raw frames from animations (video mails) would be modified. Perhaps, in such cases, a filter could be applied.