[Feature Request] Merge wads / Import wad files

[simc2]

Editor

Resource editor

Description of your feature request

It is occasionally asked and answered:

Could Slade have a straightforward "Merge wads" or "Import wads" tool? - Click a tool bar button or menu item, select wads from the opening window and all the lumps and contents from them would be added after the selected lump in the currently opened wad? No more copy pasting all over for 32+ level megawads.

Currently if you are composing a wad archive the "Import Files" tool imports a wad file as a single lump (which doesn't work) and "Import Directory" imports files from a directory (which is also a no-go for wads).