Actions:
1. Remove unused functions from misc_os_dependent.h
2. Move three remaining functions, get_gmt_time, get_ns_count, and get_tick_count into time_helper.h
3. Remove unused functions from time_helper.h
4. Refactor get_ns_count and get_internet_time_str and get_time_interval_string
5. Remove/add includes as needed
Relevant commits on the old PR:
a9fbe52b029a59b131c47fa9e2817d