Switch from playbook vars to role defaults

By using role defauts, we can have inventory variables
which overide the defaults.

README.md

@@ -84,7 +84,7 @@ You can follow these steps:
 
 - copy the sample configuration file (`cp examples/host-vars.yml inventory/matrix.<your-domain>/vars.yml`)
 
-- edit the configuration file (`inventory/matrix.<your-domain>/vars.yml`) to your liking
+- edit the configuration file (`inventory/matrix.<your-domain>/vars.yml`) to your liking. You may also take a look at `roles/matrix-server/defaults.main.yml` and see if there's something you'd like to copy over and override in your `vars.yml` configuration file.
 
 - copy the sample inventory hosts file (`cp examples/hosts inventory/hosts`)
 

setup.yml

@@ -3,8 +3,5 @@
   hosts: "{{ target if target is defined else 'matrix-servers' }}"
   become: true
 
-  vars_files:
-    - vars/vars.yml
-
   roles:
     - matrix-server