Created onboardingview

Added onboardingview to the app. First use only

Apple/App/Menu/OnboardingView.swift

@@ -0,0 +1,54 @@
+//
+//  OnboardingView.swift
+//  App
+//
+//  Created by Juan Pablo Gutierrez on 25/05/23.
+//
+//  Represents the onboarding screen
+
+import SwiftUI
+
+//Sets burrow visited status
+func setVisited() {
+    UserDefaults.standard.set(true, forKey: "launchedBefore")
+}
+
+func closeApp() {
+    setVisited()
+    NSApp.windows.first?.close()
+}
+
+@available(macOS 13.0, *)
+struct OnboardingView: View {
+    var body: some View {
+        ZStack(alignment: .center) {
+            Image("OnboardingBackground")
+                .resizable(resizingMode: .stretch)
+                .aspectRatio(contentMode: .fit)
+                .scaledToFill()
+            Color.black
+                .opacity(0.6)
+                .cornerRadius(15)
+                .blur(radius: 0.2)
+                .edgesIgnoringSafeArea(.all)
+                .frame(width: 450, height: 300)
+            VStack(alignment: .center) {
+                Text("Welcome to burrow").font(.system(size: 24, weight: .bold, design: .rounded))
+                Spacer().frame(height: /*@START_MENU_TOKEN@*/20.0/*@END_MENU_TOKEN@*/)
+                Text("It is a best-in-class tool for burrowing through firewalls.").font(.system(size: 14))
+                Spacer().frame(height: 10.0)
+                Text("Built by teenagers at HackClub").font(.system(size: 14))
+                Button(action: closeApp, label: {
+                    Text("Start burrowing")
+                        .font(
+                            .system(
+                                size : 14,
+                                weight: .regular,
+                                design: .rounded))
+                        .padding(.all, 30.0)
+                        .foregroundColor(.white)
+                }).buttonBorderShape(.roundedRectangle).buttonStyle(.borderless)
+            }.padding(20.0)
+        }
+    }
+}