* Refactoring HOS folder structure
Refactoring HOS folder structure:
- Added some subfolders when needed (Following structure decided in private).
- Added some `Types` folders when needed.
- Little cleanup here and there.
- Add services placeholders for every HOS services (close#766 and #753).
* Remove Types namespaces
* Finish ISteadyClock implementation
* Implement IsStandardNetworkSystemClockAccuracySufficient
Also use signed values for offsets and TimeSpanType
* Address comments
* Fix one missing nit and improve one comment