Starting next steps on frontend for primary user creation/authentication.

* Add network.authenticateWithAssertion and related tests.
* On signup page, start the redirection code to verify with primary in new tab.
* in network.js, rename all the onSuccess to onComplete for clarity.
* Simplify tests for primary user provisioning while "not authenticated".
* Generate fake keys/certs in the provisioning mock.
* Save off the keypair/cert given to us by the provisioning frame before getting an assertion.
* Generate an assertion and log the user in on primary provisioning success.