[+] Add official APOD API from NASA.

Although there is already an heroku based keyless unofficial APOD API. Here adding an offcial API which requires APIKey.

README.md

@@ -878,6 +878,7 @@ API | Description | Auth | HTTPS | CORS |
 | [Materials Platform for Data Science](https://mpds.io) | Curated experimental data for materials science | `apiKey` | Yes | No |
 | [Minor Planet Center](http://www.asterank.com/mpc) | Asterank.com Information | No | No | Unknown |
 | [NASA](https://api.nasa.gov) | NASA data, including imagery | No | Yes | Unknown |
+| [NASA APOD (official API)](https://api.nasa.gov/planetary/apod?api_key=DEMO_KEY) | Official API for getting APOD (Astronomy Image of the Day) images along with metadata | `apiKey` | Yes | Yes |
 | [NASA APOD (unofficial API)](https://apodapi.herokuapp.com/) | API for getting APOD (Astronomy Image of the Day) images along with metadata | No | Yes | Yes |
 | [Newton](https://newton.now.sh/) | Symbolic and Arithmetic Math Calculator | No | Yes | Unknown |
 | [Numbers](https://math.tools/api/numbers/) | Number of the day, random number, number facts and anything else you want to do with numbers | `apiKey` | Yes | Yes |