Vault role updates:

* using separated vault roles for generate certs with different `O` (Organization) subject field;
  * configure vault roles for issuing certificates with different `CN` (Common name) subject field;
  * set `CN` and `O` to `kubernetes` and `etcd` certificates;
  * vault/defaults vars definition was simplified;
  * vault dirs variables defined in kubernetes-defaults foles for using
  shared tasks in etcd and kubernetes/secrets roles;
  * upgrade vault to 0.8.1;
  * generate random vault user password for each role by default;
  * fix `serial` file name for vault certs;
  * move vault auth request to issue_cert tasks;
  * enable `RBAC` in vault CI;

roles/vault/tasks/shared/gen_ca.yml

@@ -8,10 +8,10 @@
 - name: "bootstrap/gen_ca | Generate {{ gen_ca_mount_path }} root CA"
   uri:
     url: "{{ vault_leader_url }}/v1/{{ gen_ca_mount_path }}/root/generate/exported"
-    headers: "{{ vault_headers }}"
+    headers: "{{ gen_ca_vault_headers }}"
     method: POST
     body_format: json
-    body: "{{ vault_ca_options }}"
+    body: "{{ gen_ca_vault_options }}"
   register: vault_ca_gen
   delegate_to: "{{ groups.vault|first }}"
   run_once: true