add number/ordinal & number/nth

this can be useful in some cases, let's say you need to display a dynamic `1st`, `2nd`, `3rd` strings and maybe the *nth* part of the string should be formatted in a different way, let's say 1<sup>st</sup>, 2<sup>nd</sup>, 3<sup>rd</sup>... that's why I decided to break into 2 separate modules.

this will also be useful for LDML date format (#102)