Expose Ning AsyncHttpClientConfig Settings. Fixes #3353

- add a NingWsClientConfig
- setup a NingWsClientConfig Provider
- Expose the following ning settings:
- Backwards compatibility with versions <= 2.3.X

```
    ws.ning.allowPoolingConnection = Boolean
    ws.ning.allowSslConnectionPool = Boolean
    ws.ning.ioThreadMultiplier = Int
    ws.ning.maximumConnectionsPerHost = Int
    ws.ning.maximumConnectionsTotal = Int
    ws.ning.maximumNumberOfRedirects = Int
    ws.ning.maxRequestRetry = Int
    ws.ning.removeQueryParamsOnRedirect = Boolean
    ws.ning.requestCompressionLevel = Int
    ws.ning.useRawUrl = Boolean
```
Merge pull request #3361 from mattweber/ningsettings

Expose Ning AsyncHttpClientConfig Settings