Connect Sendgrid To Postfix for SMTP forwarding.

We have an Azure VM running CentOS managed using Plesk with Roundcube as the mail editor. We need to have SMTP forwarding to Sendgrid via their SMPT API on port 587and the necessary DNS records installed/modified. The login data needs putting into a file sasl_passwd on the server so that postfix forwards the outgoing email to the Sendgrid SMTP server, smtp.sendgrid.net. Access would be remote on my PC as I can access the various logins easier than handing out a bunch of passwords, I can give root access via putty.