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/.gitignore

@@ -0,0 +1,17 @@
+/.vs
+.DS_Store
+.Thumbs.db
+*.sublime*
+.idea/
+debug.log
+package-lock.json
+.vscode/settings.json
+yarn.lock
+
+/.tauri
+/target
+Cargo.lock
+node_modules/
+
+dist-js
+dist