On Outbound Gateways deprecate "request-timeout" and provide "reply-timeout" across Components

There are places where we are currently interpreting a request-timeout attribute as if it were a reply-timeout. For example, have a look at the HttpOutboundGatewayParser. We need to deprecate those attributes, replace them with reply-timeout and document clearly what that means.

This Jira serves as a parent umbrella issue. Sub-issues will be created for all affected Outbound Gateways.

E.g. see INT-2245

The parser code would basically look like this:

    IntegrationNamespaceUtils.setValueIfAttributeDefined(builder, element, "reply-timeout", "sendTimeout"); 

We could add a warn-level message for use of the then deprecated request-timeout attribute.

The real request-timeout, is actually not applicable in the first place, since the receive-timeout can be specified on a Poller element (as it should be) whenever the request-channel referenced is in fact a PollableChannel.

Important

There are valid edge-cases. E.g. The Payload Enricher when using a request channel acts like a gateway. In that case a request-timeout is perfectly valid. In fact, the wrapped Gateway in that case behaves more like an Inbound Gateway. I wanted to mention this to illustrate a case where the delineation of Outbound Gateways is starting to blur.

Take a look at INT-2216 - When we update the documentation we need to make sure to mention this and explain the differences.