Polish endpoints metadata

This commit introduces manual metadata for the endpoints.all.* namespace
and polish the appendix following the work that happened in #9692

spring-boot-actuator/src/main/resources/META-INF/additional-spring-configuration-metadata.json

 {"properties": [
+  {
+    "name": "endpoints.all.enabled",
+    "type": "java.lang.Boolean",
+    "description": "Enable all endpoints.",
+    "defaultValue": true
+  },
+  {
+    "name": "endpoints.all.jmx.enabled",
+    "type": "java.lang.Boolean",
+    "description": "Enable all endpoints as JMX MBeans.",
+    "defaultValue": true
+  },
+  {
+    "name": "endpoints.all.web.enabled",
+    "type": "java.lang.Boolean",
+    "description": "Enable all endpoints as Web endpoints.",
+    "defaultValue": true
+  },
   {
     "name": "endpoints.configprops.keys-to-sanitize",
     "type": "java.lang.String[]",