Indication for when the next quarterly update is

Add an indication (probably to the goals window) of when the next quarterly update is, so that players know when to expect the goals windows to update.

Start by locating the goals window and the code that determines when quarterly updates occur. Confirm how the next update time is calculated, then identify where an indication can be shown to players. Done means the goals window clearly tells players when to expect the next quarterly update.

Written by the indexing model from the issue text.