add scripts for pkg creation for mac

release_files/darwin_pkg/postinstall

@@ -0,0 +1,31 @@
+#!/bin/sh
+
+APP=/Applications/NetBird.app
+AGENT=/usr/local/bin/netbird
+
+{
+    echo "Installing NetBird..."
+
+    if test -d $APP; then
+        echo "NetBird app copied successfully."
+    else
+        echo "NetBird app could not be copied to the Applications folder."
+        exit 1
+    fi
+
+    ln -s $APP/netbird $AGENT
+    if test -f $AGENT; then
+        echo "NetBird binary linked successfully."
+    else
+        echo "NetBird could not create symlink to /usr/local/bin"
+        exit 1
+    fi
+
+    $AGENT service install
+    $AGENT service start
+
+    open $APP
+
+    echo "Finished Netbird installation successfully"
+    exit 0 # all good
+} > /tmp/my_postinstall.log