Confusing default `window` & `frequency` combination for metrics alerts

[alahiff]

The methods create_metric_range_alert and create_metric_threshold_alert have by default:

• frequency: 1
• window: 5

Since most users would probably assume the same values are used for both, the results are very confusing and it looks like something is wrong. Please change the default window to 1. Or even better, set window to the same value as frequency if the user doesn't explicitly define window.