Try clearing any website data from your browser. I was having this same issue and it seems like the browser was saving some kind of old permissions. After clearing my browser's cache/website data I can see the "keys" tab.

I'll put my 2 cents in here. This has drastically hurt development for countless people along with my own company. Install times are very slow and causing many headaches. On top of that the following issues have shown up for me personally. Debugging offline functionality is completely broken. The apps now have to be verified by the internet before you can run them on the install device. This makes development impossible for anyone without an internet connection. The simulator is not a fallback when using hardware specific features. Due to just those two points creating new features for a client specific app has come to a crawl. And those of us who work remotely and may lose internet are left in a state where we cannot work. This needs to be reversed in a timely manner. There is no excuse in my mind as to why Apple would do this. The only thing I can think of is they plan on taking away the port all together, which I think is a terrible idea. It looks like many enterprise developers who are required to work under a VPN are blocked as well. Can't imagine that will look good for Apple.