Fixing broken Binder links

[brian-rose]

Currently most of our Cookbooks are failing their nightly health checks due a bad link, e.g.
https://github.com/ProjectPythiaCookbooks/HRRR-AWS-cookbook/runs/7778415916?check_suite_focus=true

The cause is that the Pangeo Binder service at https://binder-staging.2i2c.cloud is permanently offline.

As discussed at today's IWG, we are hoping to direct Cookbooks to a dedicated BinderHub running on JetStream2, but it is not ready for prime time just yet.

In the mean time we will redirect all Cookbook binder links to mybinder.org

[brian-rose]

We never finished this -- some cookbook repos are still failing the link check due to the broken binder link.

But this will be superseded by #96.

[brian-rose]

I think we finally finished this while addressing #96. Closing.