doc(weatherAPI): add few documentation

src/main/java/eirb/pg203/Temperature.java

@@ -13,14 +13,26 @@ public class Temperature {
         this.date = date;
     }
 
+    /**
+     * Get the name of the city from where the temperature come from
+     * @return city
+     */
     public String getCity() {
         return city;
     }
 
+    /**
+     * Get the date
+     * @return date
+     */
     public Instant getDate() {
         return date;
     }
 
+    /**
+     * Get the temperature
+     * @return temperature
+     */
     public float getTemp() {
         return temp;
     }

src/main/java/eirb/pg203/WeatherDataAPI.java

@@ -5,11 +5,30 @@ import java.util.ArrayList;
 
 public interface WeatherDataAPI {
 
+    /**
+     * Fetch the temperature for a specific day in a city
+     * @param day Since D+0
+     * @param city Localisation
+     * @return Temperature of the day from the city
+     * @throws IOException when request failed
+     */
     Temperature getTemperature(int day, String city) throws IOException;
 
+    /**
+     *
+     * @param day Since D+0
+     * @param hour Since H+0
+     * @param city Localisation
+     * @return Temperature of the day for a hour from the city
+     * @throws IOException when request failed
+     */
     Temperature getTemperature(int day, int hour, String city) throws IOException;
 
     ArrayList<Temperature> getTemperatures(int days, String city) throws IOException;
 
+    /***
+     * Name of the API
+     * @return Name of the API
+     */
     String getAPIName();
 }