This adds two config items: useAbsoluteTimeFormat (boolean) and
absoluteTimeFormatMinAge (string, number + unit ('d'|'h'|'m'|'s')).
When `useAbsoluteTimeFormat` is true, the Timeago component will display
absolute time if the time is at least `absoluteTimeFormatMinAge`
from now. If `longFormat` prop is true, the fully formatted time
is displayed. Otherwise, the format is determined by the `time` prop:
(1) if `time` is on the same day of now, display hour and minute;
(2) if `time` is in the same month of now, display day and hour;
(3) if `time` is in the same year of now, display month and day;
(4) otherwise, display year and month.
If it should display relative time, the format is the same as before.
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