Lib/time todo

[litlighilit]

trace for progress

• update readme examples (it used to use std/os.sleep, with msg in milisecs unit)
• handle zone
• sleep shall accept float, too
• impl strftime
• impl strptime
• check if strptime causes dst issue
• impl stuct_time(tuple)
• time_* and consts
• atime asctime
• tests
• solve ci failure when JS
• add according include::xxx.rst directive in time.strftime/strptime
• struct_time.repr

[litlighilit]

for locale strftime/strptime:

• doc it that current those format that shall be locale-aware is ISO only.

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it's possible to aquire the locale-aware format presentation to init the DateTimeLocale from C's strftime / C++'s chrono Formatter, but not sure if necessary, as Nim itself is locale independent.