Before deprecating `TestRestTemplate`, we must first stop using it in
smoke tests and replace it with:
* `RestTestClient` when the Spring MVC infrastructure is present
* `RestClient` when the test does not have Spring MVC on classpath
See gh-46632
Create `spring-boot-resttestclient` and `spring-boot-webtestclient`
modules to hold test client auto-configuration and `TestRestTemplate`
code.
Previous these classes were contained in `spring-boot-resetclient-test`
and `spring-boot-webclient-test` which was incorrect since the `-test`
modules should hold code need to test the given modules, not supporting
test classes.
See gh-46356
Co-authored-by: Phillip Webb <phil.webb@broadcom.com>
Relocate `RestTestClientBuilderCustomizer` to `spring-boot-test`
and break the direct link to web-server by making use of
`spring.factories` and the new `BaseUrlProviders` class.
See gh-46356
Brian Clozel
Andy Wilkinson
