switch settings to en-gb and Europe/London TZ

[marcelkornblum]

https://uktrade.atlassian.net/browse/DWPF-161

Not 100% convinced this is a great idea, though it's definitely nicer user experience for e.g. article published date. Any watch-outs you can think of, perhaps re: infra, logging, etc?

[CamLamb]

It might be worth double checking, but I think TIME_ZONE might be used when storing dates/datetimes.
If it is, then you might want to either:

• Write a migration (could be a task and a half!)
• See if there is a way to set the default current time zone https://docs.djangoproject.com/en/4.2/topics/i18n/timezones/#default-time-zone-and-current-time-zone

[CamLamb]

LGTM, nice n simple!