Upgrade HttpComponentsHIRE to HttpComponents 4.3

Previously, HttpComponentsHttpInvokerRequestExecutor was not compatible
with the new API of HttpComponents 4.3. Specifically, it is not possible
to update the socket and read timeouts on the HttpClient itself anymore.

We actually already updated HttpComponentsClientHttpRequestFactory for a
similar problem in SPR-11442: if we detect an older HttpClient
implementation, we update the timeout directly on the client. If that's
not the case, we keep the value in the factory itself and use it when a
new HttpRequest needs to be created.

This commit also uses the new API to create a default HttpClient and
therefore requires HttpComponents 4.3. As mentioned above, it is still
possible to use deprecated HttpClient instances against this executor.

Issue: SPR-11113