Remove Sentium, it's broken

Sentium returns http code 503 when accessed

README.md

@@ -1617,7 +1617,6 @@ API | Description | Auth | HTTPS | CORS |
 | [LibreTranslate](https://libretranslate.com/docs) | Translation tool with 17 available languages | No | Yes | Unknown |
 | [Semantria](https://semantria.readme.io/docs) | Text Analytics with sentiment analysis, categorization & named entity extraction | `OAuth` | Yes | Unknown |
 | [Sentiment Analysis](https://www.meaningcloud.com/developer/sentiment-analysis) | Multilingual sentiment analysis of texts from different sources | `apiKey` | Yes | Yes |
-| [Sentium](https://sentim-api.herokuapp.com/) | Free API for Text Sentimental analysis | No | Yes | Unknown |
 | [Tisane](https://tisane.ai/) | Text Analytics with focus on detection of abusive content and law enforcement applications | `OAuth` | Yes | Yes |
 | [Watson Natural Language Understanding](https://cloud.ibm.com/apidocs/natural-language-understanding/natural-language-understanding) | Natural language processing for advanced text analysis | `OAuth` | Yes | Unknown |