Add WUnderground WeatherProvider with Zimmerman PWS support

types.ts

@@ -1,6 +1,9 @@
 /** Geographic coordinates. The 1st element is the latitude, and the 2nd element is the longitude. */
 export type GeoCoordinates = [number, number];
 
+/** A PWS ID and API key. */
+export type PWS = { id: string, apiKey: string };
+
 export interface TimeData {
     /** The UTC offset, in minutes. This uses POSIX offsets, which are the negation of typically used offsets
      * (https://github.com/eggert/tz/blob/2017b/etcetera#L36-L42).
@@ -71,4 +74,4 @@ export interface ZimmermanWateringData extends BaseWateringData {
     raining: boolean;
 }
 
-export type WeatherProviderId = "OWM" | "DarkSky" | "local" | "mock";
+export type WeatherProviderId = "OWM" | "DarkSky" | "local" | "mock" | "WUnderground";