Authenticate Users for DHS website
authenticate_dhs(config)
Returns list of length 3:
user_name: your email usually
user_pass: your password you provided
proj_id: your project number
If the user has more than one project that contains the first 30 characters of the provided project they will be prompted to choose which project they want. This choice will be saved so they do not have to enter it again in this R session.
Credit for some of the function to https://github.com/ajdamico/lodown/blob/master/R/dhs.R