Allow service contact details to be phone number, email or url

Service contact details are needed if the upload document permission is
enabled - this used to be a link but services can now choose to use a
link, email address or phone number. The form to add or change service
contact details now gives these options and validates the data according
to the type of contact details provided.

When validating phone numbers we can't use the existing validation
because we want to allow landlines too, so there is a basic check that
the phone number is the right length and doesn't include certain
characters.

app/assets/javascripts/main.js

@@ -2,6 +2,9 @@ $(() => $("time.timeago").timeago());
 
 $(() => GOVUK.stickAtTopWhenScrolling.init());
 
+var showHideContent = new GOVUK.ShowHideContent();
+showHideContent.init();
+
 $(() => GOVUK.modules.start());
 
 $(() => $('.error-message').eq(0).parent('label').next('input').trigger('focus'));