undocument AOT support

* it could break apps that had AOT'ed some migration library like flyway during build, which would need some extra code (java) to not automatically use them at runtime (and training run...)
see: spring-projects/spring-boot#41348
* after confirmation we won't ever re introduce AOT support along with CDS in Spring Boot buildpack, we'll deprecate the feature

README.md

@@ -28,9 +28,6 @@ The buildpack will do the following:
       * Contributes application slices as defined by the layer's index
     * If the application is a reactive web application
       * Configures `$BPL_JVM_THREAD_COUNT` to 50
-    * If the application is AOT instrumented (presence of `META-INF/native-image` folder) AND `BP_SPRING_AOT_ENABLED` is set to `true`
-      * set `BPL_SPRING_AOT_ENABLED` to true
-      * add `-Dspring.aot.enabled=true` to `JAVA_TOOL_OPTIONS` at runtime
 * If `<APPLICATION_ROOT>/META-INF/MANIFEST.MF` contains a `Spring-Boot-Native-Processed` entry OR if `$BP_MAVEN_ACTIVE_PROFILES` contains the `native` profile:
   * A build plan entry is provided, `native-image-application`, which can be required by the `native-image` [buildpack](https://github.com/paketo-buildpacks/native-image) to automatically trigger a native image build
 * When contributing to a native image application:
@@ -46,8 +43,6 @@ The buildpack will do the following:
 | `$BPL_SPRING_CLOUD_BINDINGS_DISABLED` | Whether to auto-configure Spring Boot environment properties from bindings at runtime. This requires Spring Cloud Bindings to have been installed at build time or it will do nothing. Defaults to false.                                                               |
 | `$BPL_SPRING_CLOUD_BINDINGS_ENABLED`  | Deprecated in favour of `$BPL_SPRING_CLOUD_BINDINGS_DISABLED`. Whether to auto-configure Spring Boot environment properties from bindings at runtime. This requires Spring Cloud Bindings to have been installed at build time or it will do nothing. Defaults to true. |
 | `$BP_SPRING_CLOUD_BINDINGS_VERSION`   | Explicit version of Spring Cloud Bindings library to install.                                                                                                                                                                                                           |
-| `$BP_SPRING_AOT_ENABLED`              | Whether to contribute `$BPL_SPRING_AOT_ENABLED` at runtime. Beware that the Spring Boot app needs to have been AOT instrumented (presence of `META-INF/native-image`) too. Defaults to false.                                                                           |
-| `$BPL_SPRING_AOT_ENABLED`             | Whether to contribute `-Dspring.aot.enabled=true` to `JAVA_TOOL_OPTIONS` at runtime. Defaults to yes if the above conditions were met; false otherwise                                                                                                                  |                                                                                                           
 | `$BP_JVM_CDS_ENABLED`                 | Whether to perform the CDS training run (that will generate the caching file `application.jsa`). Defaults to false.                                                                                                                                                     |
 | `$CDS_TRAINING_JAVA_TOOL_OPTIONS`     | Allow the user to override the default `JAVA_TOOL_OPTIONS`, only for the CDS training run. Useful to configure your app not to reach external services during training run for example.                                                                                 |
 | `$BPL_JVM_CDS_ENABLED`                | Whether to load the CDS caching file (`-XX:SharedArchiveFile=application.jsa`) that was generated during the CDS training run. Defaults to the value of `BP_JVM_CDS_ENABLED`                                                                                            |