### Description

Support mounting to multiple namespaces with the Hashicorp Vault Secrets Back-end

### Use case/motivation

As a data engineer I wish to utilize secrets stored in multiple mount paths (to support connecting to multiple namespaces)  without having to mount to a higher up namespace.

### Related issues

_No response_

### Are you willing to submit a PR?

- [ ] Yes I am willing to submit a PR!

### Code of Conduct

- [X] I agree to follow this project's [Code of Conduct](https://github.com/apache/airflow/blob/main/CODE_OF_CONDUCT.md)

"""
    Retrieves Connections and Variables from Hashicorp Vault.
    Configurable via ``airflow.cfg`` as follows:
    .. code-block:: ini
        [secrets]
        backend = airflow.providers.hashicorp.secrets.vault.VaultBackend
        backend_kwargs = {
            "connections_path": "connections",
            "url": "http://127.0.0.1:8200",
            "mount_point": "airflow"
            }
    For example, if your keys are under ``connections`` path in ``airflow`` mount_point, this
    would be accessible if you provide ``{"connections_path": "connections"}`` and request
    conn_id ``smtp_default``.
    :param connections_path: Specifies the path of the secret to read to get Connections.
        (default: 'connections'). If set to None (null), requests for connections will not be sent to Vault.
    :param variables_path: Specifies the path of the secret to read to get Variable.
        (default: 'variables'). If set to None (null), requests for variables will not be sent to Vault.
    :param config_path: Specifies the path of the secret to read Airflow Configurations
        (default: 'config'). If set to None (null), requests for configurations will not be sent to Vault.
    :param url: Base URL for the Vault instance being addressed.
    :param auth_type: Authentication Type for Vault. Default is ``token``. Available values are:
        ('approle', 'aws_iam', 'azure', 'github', 'gcp', 'kubernetes', 'ldap', 'radius', 'token', 'userpass')
    :param auth_mount_point: It can be used to define mount_point for authentication chosen