Modified return value for ipavault module.

The ipavault module was returning a single string value when retrieving
data. To keep consistency with other modules, it should return a dict
with the `data` variable in it.

This change modifies the result of ipavault to be a dict and also fixes
relevant tests, examples and documentation.

playbooks/vault/retrive-data-symmetric-vault.yml

@@ -14,4 +14,4 @@
         state: retrieved
       register: result
     - debug:
-        msg: "{{ result.data | b64decode }}"
+        msg: "{{ result.vault.data }}"