Add fix for email on install.

[Decipher]

When installing, more often than not it will fail due to trying to send an email.

Fix is simple, append the si with:

/usr/bin/env PHP_OPTIONS="-d sendmail_path=`which true`" 

[christopher-hopper]

How about also adding configuration variables for:

• account email - uid1 email. Defaults to admin@example.com
• site email - From: address for system mailings. Defaults to admin@example.com

Suggest additions for defaults/main.yml:

drupal_account_mail: "admin@example.com"
drupal_site_mail: "{{ drupal_account_mail | default('admin@example.com') }}"