deprod: Clean up; convert to use Morebits.batchOperation

Nothing that hasn't been done before in previous commits.

The only lingering issue here is that Morebits.wikitext.template.parse is
really buggy, and seems to have problems with the common case of multiple
piped wikilinks inside template parameters. That really needs to be fixed.
batchdelete: Add capability to delete associated talk pages

Seems like a useful thing to have.
batchdelete: Unify initial query logic

"imageinfo" will be used in the subsequent commit.

Also renaming a variable to avoid collisions with reserved words.
batchdelete: Merge in some logic from delimages

Merging in the logic for displaying initial contributors, and unlinking
image instances.

This paves the way for a potential deletion of the delimages module. The
logic allowing the deletion of all images displayed on a page is not
available in batchdelete, but it is of questionable usefulness. If anyone
says they want it, we can add it back later.