[native/sqlite] introduce function to get database version

Summary: In the future there will be a need to get the database version in different places, that being said extracting logic to separate function.

Test Plan: Check if logged database version is propper (could be compared with user_version visible after connecting to the database).

Reviewers: marcin, jon, atul, tomek

Reviewed By: marcin, atul, tomek

Subscribers: ashoat, tomek, atul, abosh

Differential Revision: https://phab.comm.dev/D5375