Support additional derives for Enums

[FlyinPancake]

Problem

I use utoipa which needs all types in it to implement ToSchema however adding the flag --model-extra-derives=ToSchema to sea generate does not add ToSchema to the Enms in sea_orm_active_enums.rs.

Solution

1. Add a new flag i.e.: --enum-extra-derives
2. Add additional derives from --model-extra-derives to enums as well (not preferred)