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/app/.gitignore

@@ -0,0 +1,6 @@
+/src/main/java/com/kkrainbow/easytier/generated
+/src/main/jniLibs/**/*.so
+/src/main/assets/tauri.conf.json
+/tauri.build.gradle.kts
+/proguard-tauri.pro
+/tauri.properties