Add boot-java.hints.on config key back

The information about this config key was lost
from vscode-boot-java in the merge to vscode
spring-boot.

Adding it back.

vscode-extensions/vscode-spring-boot/package.json

@@ -55,6 +55,17 @@
         "configuration": "./properties-support/language-configuration.json"
       }
     ],
+    "configuration": {
+      "type": "object",
+      "title": "Boot-Java Configuration",
+      "properties": {
+        "boot-java.boot-hints.on": {
+          "type": "boolean",
+          "default": true,
+          "description": "Enable/Disable Spring running Boot application live hints decorators in the source code"
+        }
+      }
+    },
     "grammars": [
       {
         "language": "spring-boot-properties-yaml",