Implement interface for translation from raw message string into SQLite database entities

Summary: Defines in C++ functions that are implemented in message-ops-utils.js

Test Plan: No testing plan. Future diffs will introduce code that was used on iOS and Andrdoid to parse raw message strings and store them in database.

Reviewers: palys-swm, karol-bisztyga

Reviewed By: palys-swm, karol-bisztyga

Subscribers: geekbrother, jimpo, ashoat, Adrian, atul, yayabosh

Differential Revision: https://phab.comm.dev/D3941