Low-code CDK: Allow configuration of param injection method in oauth authenticator

### What area the feature impact?

None

### Revelant Information

Currently the base oauth authenticator class is passing parameters to the token refresh endpoint as form-encoded body.

As this is not always the right approach, the oauth authenticator should be extended to allow sending the parameters as json body or as request parameters as well.

YAML extension:
```
OAuthAuthenticator:
properties:
request_type:
type: string
enum: [request_parameter, body_data, body_json]
```

The new parameter is optional, if not set it behaves as if it's set to `body_data`.

If it's set to `body_json`, the payload is encoded as a json body and the content-type header is set accordingly.
If it's set to `request_parameter`, the payload is encoded as query parameters.

In the UI, there is a dropdown that allows the user to configure this