function cdb_loggedInUser()
Summary
This function returns the email of the logged in user (or developer), if there is one that has been authed. If no user is logged in/authed, then it returns empty.
Inputs
None
Outputs
(String) - The email of the logged in user
Examples
get cdb_auth("user@email.com","password","user")
# Assuming successful log in.
put cdb_loggedInUser()
# Output: user@email.com