Paste as bicep: Can we create new files directly in the editor for modules from nested templates?

from #1759

Right now, if you use context menu to decompile a bicep file that contains nested templates, it creates new module files on disk for those templates. But not if you paste as Bicep (you get a module reference, but the file does not exist).

Bicep discussion decided best solution is probably to create new files in the editor for the modules, and have them be unsaved.

Compare the existing context-menu decompile behavior with Paste as Bicep for nested templates, focusing on how module references are created. Done means Paste as Bicep creates the referenced module files as unsaved editor files, matching the proposed Bicep discussion outcome.

Written by the indexing model from the issue text.