HW Agent - Add the Auth Type Credentials to the Openstack Plugin

**Describe the Feature**
Add as a new type of authentication the v3applicationcredential, supported explicitly by the clouds configuration file in OpenStack. This authentication method allows users to authenticate using Application Credentials

**An Example**
```yaml
clouds:
mycloud:
auth:
auth_type: v3applicationcredential
auth_url: "https://openstack.example.com/v3"
application_credential_id: "123456789abcdef"
application_credential_secret: "application-secret"
```

@tranchis , @soniasantiago , @oriolmirolf