`@ImportHttpServices` property for the `HttpExchangeAdapter` bean to use

[ch4mpy]

Enhancement request

I have some RestClient and WebClient beans already defined in the factory bean (with advanced auto-configuration for HTTP proxy, request authorization, SSL bundles, base-URL, ...).

It would be helpful if @ImportHttpServices accepted a reference to the HttpExchangeAdapter bean to use when building the service proxy.

For instance:

@Configuration
@ImportHttpServices(group = "bidule", types = {BiduleApi.class}, adapter = "biduleClientAdapter")
@ImportHttpServices(group = "machin", types = {MachinApi.class}, adapter = "machinClientAdapter")
public class RestConfiguration {
  @Bean
  RestClientAdapter biduleClientAdapter(RestClient biduleClient) {
    return RestClientAdapter.create(biduleClient);
  }

  @Bean
  RestClientAdapter machinClientAdapter(RestClient machinClient) {
    return RestClientAdapter.create(machinClient);
  }
}

[rstoyanchev]

We'll handle this under #35707.