Deprecate PrePostTemplateDefaults

Since there is nothing specific to configuring pre/post
annotations, there is no need for the extra class.

If a need like this does arise in the future,
either AnnotationTemplateExpressionDefaults can be sub-
classed, or it can have introduced a Map field holding
custom properties.

Issue gh-15286

docs/modules/ROOT/pages/servlet/authorization/method-security.adoc

@@ -1012,8 +1012,8 @@ Java::
 [source,java,role="primary"]
 ----
 @Bean
-static PrePostTemplateDefaults prePostTemplateDefaults() {
-	return new PrePostTemplateDefaults();
+static AnnotationTemplateExpressionDefaults templateExpressionDefaults() {
+	return new AnnotationTemplateExpressionDefaults();
 }
 ----
 
@@ -1023,8 +1023,8 @@ Kotlin::
 ----
 companion object {
     @Bean
-    fun prePostTemplateDefaults(): PrePostTemplateDefaults {
-        return PrePostTemplateDefaults()
+    fun templateExpressionDefaults(): AnnotationTemplateExpressionDefaults {
+        return AnnotationTemplateExpressionDefaults()
     }
 }
 ----