Rename subrole facts -> init

Trying to improve the name, `init` needs to be loaded before calling other
subroles.

We don't make `init` a dependency of `common`, `masters` and `nodes` to
avoid running the relatively slow `openshift_facts` multiple times.

playbooks/byo/openshift-preflight/check.yml

@@ -1,7 +1,7 @@
 ---
 - hosts: OSEv3
   roles:
-    - openshift_preflight/facts
+    - openshift_preflight/init
 
 - hosts: OSEv3
   name: checks that apply to all hosts

roles/openshift_preflight/README.md

@@ -24,9 +24,8 @@ Example Playbook
 ```yaml
 ---
 - hosts: OSEv3
-  gather_facts: no
   roles:
-    - openshift_preflight/facts
+    - openshift_preflight/init
 
 - hosts: OSEv3
   name: checks that apply to all hosts