Enh: edit-list.py could retrieve less data

The query currently fetches all the source fields.
However only a few are actually needed (body, subject, from) and then only if the obfuscate option is used. In other cases the source is not needed at all.

Start in edit-list.py and inspect the query that currently selects all source fields. Compare the path when obfuscate is enabled with paths that do not use source data, focusing on body, subject, and from. Done means non-obfuscation cases avoid retrieving source data while obfuscation still has the fields it needs.

Written by the indexing model from the issue text.