Standardise format for date location

[karthikb351]

Currently, our event websites and funnel use a datelocation field to indicate the date and location of an event. This is a freeform text field that's shown as-is next to the event information

The reason it is a freeform field, and not constructed from the date and venue data is so it's flexible for cases where the event might not be so straightforward.

This, however, is a double-edged sword as the lack of a format has made it wildly inconsistent based on who has entered the data, like on talkfunnel.com

On hasgeek.com, however, the datelocation field in the UI is generated from the start_time, end_time, and city information, with little tweaks like ignoring the time component when the event is more than a single day. (Relevant code)

I favor the hasgeek.com approach, and to generate the field from fixed data. If there any exceptions, it'll force us to model a solution to that problem, like multi-day events (For example, every Sunday for 4 weeks) - which we haven't really discussed yet.

[mediatinker]

Of course I am going to rule on the side of regularity. start_time, end_time, city FTW. Datelocation is madness.

But I will note that the format has too many commas and meridians should be lowercase. From our official style sheet:
Dates
Thursday 11 May 2017
11–12 May 2017 [note en dash]
Times
24h 00:00, 09:30, 14:15, 23:59
12h 9:00 am, 11:30 pm

So please fix that, too, while you're digging about in the code. Thanks.