Where has iTunes "Summary" gone
Yes, both the Summary and encrypt local backup options are available.

To view the Summary

Before you can view the summary of any device, you first need to connect it via cable to your Mac and have iTunes running. Once you've done this, if your Sidebar is visible, your device will appear in the list (which is probably where you've been looking). However, this is not where you can access the Summary from. 

Instead, near the top left where the drop-down menu is to select from Music, Movies, etc you will now see on the right of it a device icon. Click on that to view the Summary for the connected device.

Encrypt backup

Once you've got the Summary up (as per above) you will see a Backups section in the centre of the screen. It is from there you can enable the encrypt backup option.