Add basic menubar

This includes a Developer menu that can be enabled or disabled through
the UI.

app/menu/main-menu.js

@@ -0,0 +1,76 @@
+const {Menu} = require('electron');
+const electron = require('electron');
+const app = electron.app;
+
+const template = [
+  {
+    label: 'Edit',
+    submenu: [
+      {
+        role: 'undo'
+      },
+      {
+        role: 'redo'
+      },
+      {
+        type: 'separator'
+      },
+      {
+        role: 'cut'
+      },
+      {
+        role: 'copy'
+      },
+      {
+        role: 'paste'
+      },
+      {
+        role: 'delete'
+      },
+      {
+        role: 'selectall'
+      }
+    ]
+  },
+  {
+    label: 'Help',
+    submenu: [
+      {
+        label: 'FAQ',
+        click () { require('electron').shell.openExternal('https://lbry.io/faq') }
+      }
+    ]
+  }
+];
+
+module.exports = {
+  showNormalMenubar: () => {
+    const menu = Menu.buildFromTemplate(template);
+    Menu.setApplicationMenu(menu);
+  },
+  showDeveloperMenubar: () => {
+    const devTemplate = template.slice();
+    devTemplate.push({
+      label: 'Developer',
+      submenu: [
+        {
+          label: 'Reload',
+          accelerator: 'CmdOrCtrl+R',
+          click (item, focusedWindow) {
+            if (focusedWindow) focusedWindow.reload()
+          }
+        },
+        {
+          label: 'Toggle Developer Tools',
+          accelerator: process.platform === 'darwin' ? 'Alt+Command+I' : 'Ctrl+Shift+I',
+          click (item, focusedWindow) {
+            if (focusedWindow) focusedWindow.webContents.toggleDevTools()
+          }
+        },
+      ]
+    });
+
+    const menu = Menu.buildFromTemplate(devTemplate);
+    Menu.setApplicationMenu(menu);
+  }
+};