[native][web] Add a timestamp column to threads table

Summary:
Create a new column where timestamps are stored.

https://linear.app/comm/issue/ENG-8751/add-a-timestamps-property-to-a-thick-thread-info

Test Plan: On native and web check if the migration succeeds. Also, clear the db and run the app to make sure creating new schema works.

Reviewers: kamil, inka

Reviewed By: inka

Subscribers: ashoat

Differential Revision: https://phab.comm.dev/D13211