Add Support for Gotify

**Is your feature request related to a problem? Please describe.**
N/A

**Describe the solution you'd like**

Add support for the Gotify push notification service

**https://gotify.net/docs/pushmsg**

**Describe alternatives you've considered**

$ curl "https://push.example.de/message?token=<apptoken>" -F "title=my title" -F "message=my message" -F "priority=5"


**Additional context**
N/A
