Dynamic period in cheat report insights

[Sesquipedalism]

Insights in cheat reports should have a different period for each player, based on the earliest game in the data considered by Kaladin.

Sometimes this will be less than 180 days (for very active players), other time it will be longer than 180 days (for players who haven't played in a TC for some time).

[Sesquipedalism]

Feedback from mods: it would be nice not to add /period:180 if all the player's games are less than half a year old. It would also be nice to use /period:182 (182 not 180) because then the corresponding radio button would become selected in the insights.