macOS: Fix WireGuardNetworkExtensionmacOS target

- Build using common network extension code
- Add run scripts
- Set Info.plist to common network extension's Info.plist
- Move entitlements to common network extension folder
- Remove Xcode-generated macOS network extension code
- Set Swift-Obj-C bridging header

Signed-off-by: Roopesh Chander <roop@roopc.net>

WireGuard/WireGuardNetworkExtension/WireGuardNetworkExtension_macOS.entitlements

@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+    <key>com.apple.security.app-sandbox</key>
+    <true/>
+	<key>com.apple.developer.networking.networkextension</key>
+	<array>
+		<string>packet-tunnel-provider</string>
+	</array>
+</dict>
+</plist>