Generate the AutoConfiguration.imports file from annotations

This commit adds the `AutoConfigurationImportsAnnotationProcessor` to
the `spring-boot-autoconfigure-processor` annotation processor
module. When added to a project build, the annotation processor will
generate the
`org.springframework.boot.autoconfigure.AutoConfiguration.imports`
file automatically from `@AutoConfiguration`-annotated classes. It
also applies the annotation processor to the Spring Boot build.

Closes gh-31228

spring-boot-system-tests/spring-boot-deployment-tests/build.gradle

@@ -17,6 +17,8 @@ configurations.all {
 }
 
 dependencies {
+	annotationProcessor(project(":spring-boot-project:spring-boot-tools:spring-boot-autoconfigure-processor"))
+
 	implementation(project(":spring-boot-project:spring-boot-starters:spring-boot-starter-web")) {
 		exclude group: "org.hibernate.validator"
 	}

spring-boot-system-tests/spring-boot-deployment-tests/src/main/resources/META-INF/spring/org.springframework.boot.autoconfigure.AutoConfiguration.imports

@@ -1 +0,0 @@
-sample.autoconfig.ExampleAutoConfiguration