Implement priority filtering, rename package, preset URL, update remotes

app/src/main/kotlin/com/github/gotifycustom/messages/Extras.kt

@@ -0,0 +1,38 @@
+package com.github.gotifycustom.messages
+
+import com.github.gotify.client.model.Message
+
+internal object Extras {
+    fun useMarkdown(message: Message): Boolean = useMarkdown(message.extras)
+
+    fun useMarkdown(extras: Map<String, Any>?): Boolean {
+        if (extras == null) {
+            return false
+        }
+
+        val display: Any? = extras["client::display"]
+        if (display !is Map<*, *>) {
+            return false
+        }
+
+        return "text/markdown" == display["contentType"]
+    }
+
+    fun <T> getNestedValue(clazz: Class<T>, extras: Map<String, Any>?, vararg keys: String): T? {
+        var value: Any? = extras
+
+        keys.forEach { key ->
+            if (value == null) {
+                return null
+            }
+
+            value = (value as Map<*, *>)[key]
+        }
+
+        if (!clazz.isInstance(value)) {
+            return null
+        }
+
+        return clazz.cast(value)
+    }
+}