New "Elderly check-in" visit reason and improved visit exports

We just added a new "Elderly check-in" visit reason. This is a request that came from a number of churches, as it's common for elders and deacons to regularly visit elderly members in addition to their annual home visits.

This reason is only available when at least one of the members being visited is 65 years or older, helping prevent it from being used unintentionally for younger members.

We've also improved the Excel and CSV visit exports by including additional fields — most notably the "Notes" field. As always, visit notes are only included if you have permission to view them, based on your church's visit note visibility settings.