## Context
We have a non-nullable constraint on authorId in attachments and
documents, until we have soft-deletion we need to handle deletion of
workspace-members and their attachments/documents.
This PR introduces pre-hooks to deleteOne/deleteMany
This is called when a user deletes a workspace-member from the members
page
Next: needs to be done on user level as well. This is called when users
try to delete their own accounts. I've seen other issues such as
re-creating a user with a previously used email failing.
This PR is dropping the column `targetColumnMap` of fieldMetadata
entities.
The goal of this column was to properly map field to their respecting
column in the table.
We decide to drop it and instead compute the column name on the fly when
we need it, as it's more easier to support.
Some parts of the code has been refactored to try making implementation
of composite type more easier to understand and maintain.
Fix#3760
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Co-authored-by: Charles Bochet <charles@twenty.com>
