[hooks/syncschema] Turn DropColumnOp into a data operation
While writing a test for a migration issue where "NOT NULL" was added to
an inlined relation column, I ran into a case where the same column was
deleted twice, which of course results in an error. This is because the
"ecrit_par" relation used by the test is ambiguous. I've hence turned
the DropColumnOp into a data operation to ensure we'll delete the column
only once in such case.
Related to #6211101
action box
Area visible in the upper left column. You have a list of available actions on the entity. The most frequently used entry is `modify`.
object
All element created in the application
Example: project, ticket, user, ...
relation editing module
HTML widget that let you define new relations amongst objects.
relation
It's a kind of 'smart' link between 2 objets of the application. It has a specific sense that determine dynamic behaviour and add a new logic of the content.