Migration to populate filledBy

[mahalakshme]

Need:

• Needed to be able to write report card queries so that it doesn't miss out displaying any subjects in the result

Acceptance criteria:

• For the org in focus alone(Teach AP app), add migration to populate filledBy field with lastModifiedBy field in server for encounter table.

Out of scope:

• No need to do anything for createdBy and lastModifiedBy related audit fields since they will be handled by fresh sync.
  createdBy, lastModifiedBy and filledBy fields in the client will get populated when users do fresh sync when the new infra is setup

Tech notes:

• Not flyway migration

[mahalakshme]

Moving to Hold since need confirmation from the client if the above approach is fine. Same will be discussed during showcase.

[petmongrels]

accidentally picked up. WIP query has been checked in here -
https://github.com/avniproject/data-fixes/blob/d0e0a379a484cb6a5c696c65541fe7145db2f946/lfe/filledBy.sql