Shorten URL parameters for mariadb.org/download

To better aid readability, we should try to shorten the URL if possible. See Ian's comments:

Ian Gilfillan: @Vicențiu Ciorbaru for shortening the direct download link: Currently it's https://mariadb.org/download/?tab=mariadb&release=10.7.0&product=mariadb
It would be good to default to the first tab, and reduce to one letter. What is the second mariadb for? So something like https://mariadb.org/download/?r=10.7.0

Ian Gilfillan: Or https://mariadb.org/download/?r=10.7.0&p=mariadb if there's a good reason for the second, and it can't be default

Or https://mariadb.org/download/?r=10.7.0&p=mariadb if there's a good reason for the second, and it can't be default