Fixed registration for programs and membership

When someone registered for a program/membership, we had two tabs to register: Sign Up & Sign In. One was for someone who didn't have a vstudio participant account and the other one was for someone who did. This caused a lot of confusion when registering. 

To fix this, we removed the Sign In tab so now there's only Sign Up tab when registering and if someone has an account already, we auto-check it on our end and get them signed in. 

If you have any questions, let us know at help@vstudio.live.