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>
Andy Wilkinson