Write data migration plan / test cases for terraform import script

[frank-ye]

Since the import script is essentially a data migration, we need to call out:

1. all resources to be migrated
2. are there non-migratable resources / limitations? Will entities be 1:1, n:1, 1:n?
3. what test cases will validate this? What test setups do we need?
4. are there any dependencies (if written in Python, bash, etc.)?

This ticket's artifact will be a Notion page loosely based off AC in: https://www.notion.so/astronomerio/Data-Migration-Alert-V1-Alert-V2-3ef91f45c5bf426f8d418f7353683a81