docs(notifications): add more documentation for notifications (#1856)

This PR adds more documentation methods for notifications. Most of it is taken from the Overseerr
documentation.

docs/using-jellyseerr/notifications/gotify.md

@@ -0,0 +1,21 @@
+---
+title: Gotify
+description: Configure Gotify notifications.
+sidebar_position: 5
+---
+
+# Gotify
+
+## Configuration
+
+### Server URL
+
+Set this to the URL of your Gotify server.
+
+### Application Token
+
+Add an application to your Gotify server, and set this field to the generated application token.
+
+:::info
+Please refer to the [Gotify API documentation](https://gotify.net/docs) for more details on configuring these notifications.
+:::