[DX] Switch to a simplified array syntax for database connection information in settings.php

I just tried to install Backdrop 1.5 in a local AMPPS environment. During installation, after being on the language page, I got the message

Fatal error: Class 'DatabaseTasks_' not found in {...}/core/includes/install.inc on line 1362

and wasn't able to continue the installation.

Line 1362 concerns the database driver. Googling something like drupal error database driver led me to a comment on d.org regarding Backup and Migrate about a problem with special characters in the database password string. I had a look in my settings.php, noticed a forward slash in the password string, changed the database password in the relevant places and was able to continue the installation.

Are forward slashes (and possibly particular other special characters) in the database password string not supported by Backdrop for a certain technical reason? If so, we should document it somewhere. If not, can we fix that?

ADVOCATE: @yorkshire-pudding