Mark up events with `h-event` Microformats2

[jamietanna]

To make this site accessible for Microformats2 parsers to allow a greater audience of machines, it'd be great to support the h-event Microformats2 markup on our events listings.

[chrisemerson]

I'll take this one!

[chrisemerson]

This already looks to be done - @jamietanna?

[jamietanna]

Ooh didn't realise we marked up some of it, but it'd be cool if we could have the start time on it if possible? But preferably end time and maybe even location?