Refactor reduction operations to use general ones

[scastd]

Describe the feature

Several classes in the new construct.atomic.operation package were already defined in the var.reduction one.

Objective: refactor the code into a single common package and use the operations in the reduction classes (since the interfaces do not contain the same methods).

Additional information

• [X] Would you be willing to help implement this feature?

Final checks

• [X] Read the contribution guide.
• [X] Check existing discussions and issues.