[server/validate] respond with all validation errors (#11776)

* [server/validate] respond with all validation errors

* [server/config] fail with all validation errors

src/server/config/config.js

@@ -97,7 +97,10 @@ module.exports = class Config {
       );
     }
 
-    const results = Joi.validate(newVals, this.getSchema(), { context });
+    const results = Joi.validate(newVals, this.getSchema(), {
+      context,
+      abortEarly: false
+    });
 
     if (results.error) {
       throw results.error;

src/server/http/setup_connection.js

@@ -21,6 +21,11 @@ export default function (kbnServer, server, config) {
       cors: config.get('server.cors'),
       payload: {
         maxBytes: config.get('server.maxPayloadBytes')
+      },
+      validate: {
+        options: {
+          abortEarly: false
+        }
       }
     }
   };