Add a link to create a database on install_prepare.

This is a ticket created as a kind of duplicate for https://www.drupal.org/project/documentation/issues/3489514 📌 Suggestion for: (2827301) 3.4. Preparing to Install Active as the documentation page says to open a new ticket on this module and upload the file here.

Link added on the page at:

3. Create a database, along with a database user account with full access. See Create a database.

I just realised the ticket i mentioned is under the same module. Closing this one as duplicate.