Better integration of produce_horizon and climatological_op

[vindelico]

Addressing a Problem?

Aggregation methods produce_horizon and climatological_op could be better integrated and redundancy removed.

Potential Solution

Change the period label the name to horizon and remove year coordinate in climatological_op. Rename period_as_dim argument to horizon_as_dim and use horizon_as_dim=Truein produce_horizon.

Additional context

No response

Contribution

• [X] I would be willing/able to open a Pull Request to contribute this feature.

[vindelico]

Included in #290 .