R1:459e0d2fa3f8

Tune document details in Legalpad

Summary:
Fixes T9245. These picked up some possibly-confusing metadata, like in the screenshot on T9245 where "Subscribers" appears in the middle of the page for no obvious reason.

- Make these pages a little cleaner by removing elements which aren't important for signing agreements.
- Use the last time the actual document text was updated as the modification time, not the last time the "Document" object was modified. The latter will change for trivial things like…