Fabric: Telemetry time point serialization functions
Fabric: Telemetry time point serialization functions

Summary:
Fabric's Telemetry uses `std::chrono::steady_clock::time_point`s to represent the exact moments in time when some events happen. This is the same clock that pretty much any performance tracker use (and should use), QPL included.
However, different trackers use different serializable representations of that timepoints. This diff adds functions that convert the timepoint value to UNIX Timestamp and to a number of seconds from the `steady_clock` epoch start.

Changelog: [Internal] Fabric-specific internal change.

Reviewed By: mdvacca

Differential Revision: D22887632

fbshipit-source-id: 2b51acddccee9af8071a34797b5015d6fd008394

myntra/react-native,janicduplessis/react-native,pandiaraj44/react-native,pandiaraj44/react-native,janicduplessis/react-native,myntra/react-native,arthuralee/react-native,arthuralee/react-native,hoangpham95/react-native,facebook/react-native,myntra/react-native,facebook/react-native,myntra/react-native,pandiaraj44/react-native,javache/react-native,hoangpham95/react-native,janicduplessis/react-native,facebook/react-native,janicduplessis/react-native,javache/react-native,pandiaraj44/react-native,arthuralee/react-native,javache/react-native,hoangpham95/react-native,pandiaraj44/react-native,facebook/react-native,janicduplessis/react-native,arthuralee/react-native,javache/react-native,hoangpham95/react-native,javache/react-native,javache/react-native,facebook/react-native,myntra/react-native,pandiaraj44/react-native,javache/react-native,javache/react-native,hoangpham95/react-native,hoangpham95/react-native,janicduplessis/react-native,hoangpham95/react-native,pandiaraj44/react-native,janicduplessis/react-native,myntra/react-native,myntra/react-native,myntra/react-native,janicduplessis/react-native,pandiaraj44/react-native,facebook/react-native,facebook/react-native,facebook/react-native,myntra/react-native,facebook/react-native,arthuralee/react-native,hoangpham95/react-native,javache/react-native