Minor opportunity improvements

A few improvements to "Opportunities" have been launched.

• We now let you to track “Annual” deals in your Opportunities, in addition to just “One-Time” and “Monthly” deals.
• Annual, Monthly, and One-Time deals are split up nicely in your Opportunities view.
• We now keep track of your last-used Opportunity “time period” so that you don’t have to keep selecting “monthly” each time you create a new opportunity, for example.
• Your “Opportunities” page is now sorted most-recent to least-recent for “won” and “lost” opportunities. No more continual scrolling to see your latest closed deals.