add local_time_count_down to gem

*many project need time period instead of specific
time point value. after add local_time_count_down helper
you could use this helper compare the time value with now

*change refresh frequency to 1s

*this updated gem could be use any racing project time count down staff
DRY timeGap method

*delete duplicate method part
*extract logic to individual method
Merge pull request #1 from frontfoot/feature/countdown-format

add local_time_count_down to gem