Display icon and date in CurrentForecastFragment

[n8ebel]

• Adds a date property to CurrentWeather to pull that data from the api response
• Adds a list of WeatherDescription to CurrentWeather to pull the weather description informatino from the api response. This mirrors the approach used in the WeeklyForecast model
• Moves WeatherDescription into its own file since it's reused for both CurrentWeather and WeeklyForecast
• Binds the updated CurrentWeather model into CurrentForecastFragment using the same formatting patterns as in ForecastDetailsFragment