Contrary to what you see here and other places, you can do it. But it's not pretty. It's an enterprise admin thing, but anyone can do it. Look up "Connection Profiles." Comcast does this in their iOS app to setup their hotspots for you, for example.
Basically, it's an XML document that you get the device to ingest via Safari or Mail. There's a lot of tricks to it and the user experience isn't great, but I can confirm that it works in iOS 10 and it doesn't require jailbreaking. You use Configurator to generate the XML, and I suggest this thread for serving it, and this blog for querying if it's installed.
