Android Support (#166)

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

easytier-gui/src-tauri/gen/android/buildSrc/build.gradle.kts

@@ -0,0 +1,23 @@
+plugins {
+    `kotlin-dsl`
+}
+
+gradlePlugin {
+    plugins {
+        create("pluginsForCoolKids") {
+            id = "rust"
+            implementationClass = "RustPlugin"
+        }
+    }
+}
+
+repositories {
+    google()
+    mavenCentral()
+}
+
+dependencies {
+    compileOnly(gradleApi())
+    implementation("com.android.tools.build:gradle:8.3.2")
+}
+