Make it easier to add further localised routing tests

I wanted to add the `localised: true` option to the top level `people` route
but wasn't sure where to test it. I removed all the `localised: true` options
and these were pretty much the only tests that failed, so I figured that I'd
make it easier to add tests for further localised routing changes.
Enable i18n fallbacks in development

This was triggered by me seeing warnings for missing translations when
browsing the site locally. Unless I'm actively working to find missing
translations I think I'd prefer the behaviour to be closer to that of
production, which is why I'm enabling fallbacks in development.
Add localised routing to people

This ensures that /people/<person-slug>.<locale> works correctly. Previously,
you would've had to add the '?locale=<locale>' querystring to view a person in
a different locale. This also ensures that links to people take you to the
page in the locale you're viewing the current page in.