ATL-666: Added graphics for the Windows installer.

Signed-off-by: Akos Kitta <kittaakos@typefox.io>

Author: Akos Kitta

electron/build/resources/installerSidebar.bmp

@@ -100,6 +100,11 @@
     },
     "nsis": {
       "oneClick": false,
+      "installerHeaderIcon": "resources/icon.ico",
+      "installerIcon": "resources/icon.ico",
+      "uninstallerIcon": "resources/icon.ico",
+      "installerSidebar": "resources/installerSidebar.bmp",
+      "uninstallerSidebar": "resources/installerSidebar.bmp",
       "allowToChangeInstallationDirectory": true
     },
     "dmg": {