[Feature]: Remove center_times from temporal averaging methods

[tomvothecoder]

Is your feature request related to a problem?

Centering time can be done with open_dataset/open_mfdataset` or standalone with ds.temporal.center_times()

For example, if users already ran xcdat.open_dataset(“path”, center_times=True), the center_times argument in ds.temporal.average(“ts”, center_times=True) might confuse users

Describe the solution you'd like

The user should run these commands in a series of steps by opening the dataset and centering time coordinates, then temporally averaging.

Describe alternatives you've considered

No response

Additional context

No response