Add support for selectable columns

[qdequippe]

#6669

Like insertable and updatable add support for selectable column.

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My use case: zero-downtime deployment

To ensure a zero-downtime deployment when removing a column, we need to ensure that the previous version of the code stops reading that column.

• Phase 1: Set selectable, insertable, and updatable to false, then deploy the code.
• Phase 2: Remove the property from the entity mapping and drop the column from the database (using Doctrine migrations, for example).