Add Duration support about okaeri-placeholders

[dasavick]

Added in 3827585

Expected	Pattern	Note
02:30	{%02.0f#duration.hours}:{%02.0f#duration.minutes}	use f with zero decimal places, as number formatting in okaeri-placeholders converts to double
01:02:30	{%02.0f#duration.days}:{%02.0f#duration.hours}:{%02.0f#duration.minutes}	use f with zero decimal places, as number formatting in okaeri-placeholders converts to double
2h3m, 1d2h3m	{duration} or {duration(m)}	1st param = precision, s by default
2 hours and 3 minutes, also 1 hour and 3 minutes	{duration.hours} {hour,hours#duration.hours} and {duration.minutes} {minute,minutes#duration.minutes}	-
1 day and 5 hours	{duration.days} {day,days#duration.days} and {duration.hours} {hour,hours#duration.hours}	-
1 day, 5 hours and 1 minute	{duration.days} {day,days#duration.days}, {duration.hours} {hour,hours#duration.hours} and {duration.minutes} {minute,minutes#duration.minutes}	-