[FEATURE] Redesign the (PsychoJS) hello and goodbye screens

Created by: denispelli

Is your feature request related to a problem? Please describe. What's easily changed? Show our logo! Please clean up the request for participant name. It should say "Welcome to EasyEyes Threshold."

The Hello and Goodbye screens are ugly. Describe the solution you'd like When I aborted by hitting Escape it says "Thank you for your patience." Please change "patience" to "participation."