front page awards tracker improvements

[Teffania]

From bug:
https://bugs.launchpad.net/canonlore/+bug/501502

Referring to front page award tracker: "It would Now that I see the size of this, 2-3 months may be an excessively long time. This is probably excentuated by the fact that the end of each reign, as we have now, tends to have a lot of awards. The reason I said 2-3 months was that since awards can take a month to wend their way to canon and then find time to be entered, if I said 1 month, some awards might never appear on this list. But this number is huge! Is it easy enough to calculate the most recent event with awards in it? (perhaps highest value of [canon_received:received_date] ?) If it were, then I think 1 month counting backwards from that date would be a more accurate rendering of what I would prefer to show here. This is an ammendment based on getting exactly what I asked for."

this is a wishlist item for cases of infinite programmer time.