ops(ansible): configure local vault password file

Add an ignored example-backed password file for non-interactive deployments and document the external password file override.

ansible/.vault_pass.txt.example

@@ -0,0 +1 @@
+your-vault-password

ansible/ansible.cfg

@@ -4,6 +4,7 @@ roles_path = roles
 interpreter_python = auto_silent
 host_key_checking = True
 retry_files_enabled = False
+vault_password_file = .vault_pass.txt
 
 [ssh_connection]
 ssh_args = -o StrictHostKeyChecking=accept-new