Migrate tauri from portmaster-ui to desktop/tauri. Update build system

desktop/tauri/src-tauri/src/portapi/models/spn.rs

@@ -0,0 +1,8 @@
+use serde::*;
+
+
+#[derive(Serialize, Deserialize, Debug, PartialEq, Clone)]
+pub struct SPNStatus {
+    #[serde(rename = "Status")]
+    pub status: String,
+}