Port the new user registration page to Firebase

[w7mot]

Port the registration page to Firebase. This includes the following tasks:

• [ ] Connect to Firebase
• [ ] Secure Firebase
• [x] Move the welcome page to the top level and update references.
• [ ] Create the user table structure (per StackExchange, passwords are stored as an MD5 of the password and a 32-character string salt).
• [ ] Create an SMTP2GO account
• [ ] Integrate with SMTP2GO
• [ ] Add admin notification
• [ ] Determine whether media/com_phocadownload/js/overlib/overlib_mini.js is needed and take appropriate action.

[w7mot]

References: Dynamic Web Apps on GitHub Pages FOR FREE Authenticate and manage users from a variety of providers without server-side code Firebase Authentication Jekyll blogs