Redo Events page to pull in posts by tag

[hauten]

Ideally want to create new events as _posts, then tag with event (or similar) and display just those posts on events. Would be good to match the year display and filter from /blog, which would eliminate the need for any type of archive. See https://mmistakes.github.io/minimal-mistakes/docs/collections/. This would require creating posts for each event currently on the Events page.