Android Support (#166)

1. Add vpnservice tauri plugin for android.
2. add workflow for android.
3. Easytier Core support android, allow set tun fd.

tauri-plugin-vpnservice/ios/Package.swift

@@ -0,0 +1,31 @@
+// swift-tools-version:5.3
+// The swift-tools-version declares the minimum version of Swift required to build this package.
+
+import PackageDescription
+
+let package = Package(
+    name: "tauri-plugin-vpnservice",
+    platforms: [
+        .iOS(.v13),
+    ],
+    products: [
+        // Products define the executables and libraries a package produces, and make them visible to other packages.
+        .library(
+            name: "tauri-plugin-vpnservice",
+            type: .static,
+            targets: ["tauri-plugin-vpnservice"]),
+    ],
+    dependencies: [
+        .package(name: "Tauri", path: "../.tauri/tauri-api")
+    ],
+    targets: [
+        // Targets are the basic building blocks of a package. A target can define a module or a test suite.
+        // Targets can depend on other targets in this package, and on products in packages this package depends on.
+        .target(
+            name: "tauri-plugin-vpnservice",
+            dependencies: [
+                .byName(name: "Tauri")
+            ],
+            path: "Sources")
+    ]
+)