Add news/selfoss default vars to role

roles/news/defaults/main.yml

+secret_root: '{{ inventory_dir | realpath }}'
+secret_name: 'secret'
+secret: '{{ secret_root + "/" + secret_name }}'
+
+selfoss_domain: "news.{{ domain }}"
+selfoss_db_username: selfoss
+selfoss_db_password: "{{ lookup('password', secret + '/' + 'selfoss_db_password', length=32) }}"
+selfoss_db_database: selfoss
+selfoss_version: 2.14
+
+selfoss_username: "{{ main_user_name }}"
+# this is the sha512 hash of the desired password
+selfoss_password_hash: "{{ lookup('password', secret + '/' + 'selfoss_password_hash', length=32, crypt='sha512')|hash('sha512') }}"
+
+# must match values in roles/mailserver
+db_admin_username: 'postgres'
+db_admin_password: "{{ lookup('password', secret + '/' + 'db_admin_password', length=32) }}"