Add OpenBao Topic ver 2 (#459)

- added openbao topic and toc update for new file

- content based on vault.md descriptions

Author: Andriciuc

contrib/pg_tde/documentation/docs/global-key-provider-configuration/kmip-openbao.md

@@ -0,0 +1,48 @@
+# Using OpenBao as a Key Provider
+
+You can configure `pg_tde` to use OpenBao as a global key provider for managing encryption keys securely.
+
+!!! note
+    This guide assumes that your OpenBao server is already set up and accessible. OpenBao configuration is outside the scope of this document, see [OpenBao's official documentation](https://openbao.org/docs/) for more information.
+
+## Example usage
+
+To register an OpenBao server as a global key provider:
+
+```sql
+SELECT pg_tde_add_global_key_provider_vault_v2(
+    'provider-name',
+    'url',
+    'mount',
+    'secret_token_path',
+    'ca_path'
+);
+```
+
+## Parameter descriptions
+
+* `provider-name` is the name to identify this key provider
+* `secret_token_path` is a path to the file that contains an access token with read and write access to the above mount point
+* `url` is the URL of the Vault server
+* `mount` is the mount point where the keyring should store the keys
+* [optional] `ca_path` is the path of the CA file used for SSL verification
+
+The following example is for testing purposes only. Use secure tokens and proper SSL validation in production environments:
+
+```sql
+SELECT pg_tde_add_global_key_provider_vault_v2(
+    'my-openbao-provider',
+    'https://openbao.example.com:8200',
+    'secret/data',
+    '/path/to/token_file',
+    '/path/to/ca_cert.pem'
+);
+```
+
+For more information on related functions, see the link below:
+
+[Percona pg_tde Function Reference](../functions.md){.md-button}
+
+## Next steps
+
+[Global Principal Key Configuration :material-arrow-right:](set-principal-key.md){.md-button}

contrib/pg_tde/documentation/mkdocs.yml

@@ -181,6 +181,7 @@ nav:
       - "Fortanix Configuration": global-key-provider-configuration/kmip-fortanix.md  
       - "Vault Configuration": global-key-provider-configuration/vault.md
       - "Thales Configuration": global-key-provider-configuration/kmip-thales.md
+      - "Using OpenBao as a Key Provider": global-key-provider-configuration/kmip-openbao.md
       - "Keyring File Configuration": global-key-provider-configuration/keyring.md
     - "2.2 Global Principal Key Configuration": global-key-provider-configuration/set-principal-key.md
     - "3. Validate Encryption with pg_tde": test.md