This commit adds the Jetty RS HTTP client to the Spring Boot
dependency management. As of SPR-15092 and SPR-17124, this HTTP
client library is supported by Spring Framework.

This commit is first step towards supporting that library as
a driver for the WebClient / ClientHttpConnector auto-configuration.

See gh-14005

This commit makes sure that the auto-configuration for Spring
Integration runs after the datasource has been auto-configured if
necessary as there is an optional part that can initialize the jdbc
schema.

Closes gh-14175

This commit adds support for the new `ReactorResourceFactory` and
ensures that such a bean is created and destroyed with the application
context. This will create a `ClientHttpConnector` bean, to be configured
on the `WebClient.Builder` instance - or let developers create their own
`ClientHttpConnector` bean to override that opinion.

By default, the `ReactorResourceFactory` is configured to participate
with the global resources, for better efficiency.

Closes gh-14058

* pr/14021:
  Polish "Add Kafka Streams auto-configuration"
  Add Kafka Streams auto-configuration

Closes gh-14021

See gh-14021

* pr/13837:
  Polish "Add PropertyMapper.from(value)"
  Add PropertyMapper.from(value)

Closes gh-13837

See gh-13837

* pr/14153:
  Polish "Fix String concatenation in a loop"
  Fix String concatenation in a loop

Closes gh-14153

See gh-14153

* pr/14149:
  Polish

Closes gh-14149

Closes gh-11086

Fixes gh-14136

Closes gh-14164

* pr/14152:
  Fix potential infinite recursive loop in toString

Closes gh-14152

Upgrade to M2 broke a test that was looking for a particular bean that
is configured by Spring Integration (`HeaderChannelRegistry`).

It looks like INT-4517 is related to the regression as it registers the
bean too late for the auto-configuration to see it.

This commit changes the condition to a more central bean that is created
very early on.

Closes gh-14142

Closes gh-14144

Closes gh-14123

Closes gh-14143

Closes gh-14155

Closes gh-14083

Closes gh-14081

Closes gh-14125