[ISSUE #4834] Add protocol exclusive fields filter for /v2/configuration endpoint

[Pil0tXia]

Fixes #4834

Motivation

Since EventMeshTCPConfiguration, EventMeshHTTPConfiguration and EventMeshGrpcConfiguration are subclasses of CommonConfiguration, their serialized JsonString would contain superclass fields, which enlarges the response body and brings in difficulty in getting CommonConfiguration fields.

Modifications

• Add a PropertyFilter to remove superclass fields from the JsonString of EventMeshTCPConfiguration, EventMeshHTTPConfiguration and EventMeshGrpcConfiguration, then add CommonConfiguration into the response body.
• Add configs param which accepts two values, exclusive and all.
• Add unified exception handling
• The actual version number will be returned after merging [ISSUE #4052] Implement the functionality of EventMeshVersion class.  #4055.

Documentation

• Does this pull request introduce a new feature? (yes)
• If yes, how is the feature documented? (JavaDocs)

[xwm1992]

I don’t understand the purpose of your PR modification. Why do you want to filter out the fields of the parent class? The fields of the parent class should be some common fields, and the subclass is an extension. Why do you want to filter out the common fields?
@Pil0tXia

[Pil0tXia]

The EventMesh Dashboard needs to retrieve the configuration of each EventMesh Runtime after it is connected to the cluster, store it in the database for display on the frontend pages.

Since EventMeshTCPConfiguration, EventMeshHTTPConfiguration, and EventMeshGrpcConfiguration are subclasses of CommonConfiguration, the current master branch's /v2/configuration admin endpoint will return redundant fields of CommonConfiguration in the configurations for TCP, HTTP, and GRPC. This leads to the following issues:

1. When displaying configurations on the frontend pages of EventMesh Dashboard, three copy of CommonConfiguration fields will be shown, wasting space and potentially confusing users.
2. EventMesh Dashboard needs to support maintaining multiple versions of EventMesh clusters. If EventMesh Dashboard removes duplicate fields, it needs to know which fields come from CommonConfiguration. If EventMesh Dashboard maintains a CommonConfiguration itself, but different versions of EventMesh Runtime have different CommonConfiguration, then EventMesh Dashboard will have multiple CommonConfiguration classes.
3. If EventMesh Runtime does not enable all three protocols TCP, HTTP, GRPC, and instead only enables two or one of them, EventMesh Dashboard needs to iterate over TCP, HTTP, GRPC to retrieve the values of this field when storing the fields of CommonConfiguration in the database.

These issues could have been avoided, eliminating the display of redundant content, avoiding the need to maintain the CommonConfiguration class on the EventMesh Dashboard side, and avoiding complex processing logic. This PR extracts the member fields of the CommonConfiguration class into the commonConfiguration JSON field to assist EventMesh Dashboard in distinguishing fields from CommonConfiguration.

Callers of the /v2/configuration admin endpoint can also specify the configs parameter as all, keeping the fields of CommonConfiguration in the configurations for TCP, HTTP, and GRPC.

In the future, we may consider integrating the metaStorage Plugin with ConfigService to report configurations to the registry. When we need this functionality, I can start working on this feature.

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EventMesh Dashboard需要在接入集群后，获取每一台EventMesh Runtime的配置，存入数据库中，以供前端页面上展示。

由于EventMeshTCPConfiguration、EventMeshHTTPConfiguration、EventMeshGrpcConfiguration是CommonConfiguration的子类，因此，目前master分支中/v2/configuration管理端点将会在TCP,HTTP,GRPC的配置中都返回一份CommonConfiguration的成员字段，存在冗余。这会带来以下问题：

1. EventMesh Dashboard在前端页面上显示配置时，将会显示三份一模一样的CommonConfiguration，浪费空间，容易使用户迷惑。
2. EventMesh Dashboard需要支持同时维护多个版本的EventMesh集群。如果由EventMesh Dashboard来移除重复的字段，那么EventMesh Dashboard需要知道有哪些字段来自CommonConfiguration。如果EventMesh Dashboard自行维护一个CommonConfiguration，但是不同版本的EventMesh Runtime具有不同的CommonConfiguration，那么EventMesh Dashboard就会存在多个CommonConfiguration。
3. 如果EventMesh Runtime没有开启TCP,HTTP,GRPC全部三种协议，而是只开启了其中两种或一种，则EventMesh Dashboard在将CommonConfiguration的字段存入数据库时，需要依次遍历TCP,HTTP,GRPC，获取此字段的值。

这些问题本可以被避免，不用显示重复内容，不需要在EventMesh Dashboard侧维护CommonConfiguration类，不需要复杂的处理逻辑。本PR将CommonConfiguration类中的成员字段提取到commonConfigurationJSON字段下，以帮助EventMesh Dashboard分辨来自CommonConfiguration的字段。

/v2/configuration管理端点的调用者也可以指定configs参数为all，在返回结果中保留TCP,HTTP,GRPC三种协议的配置类中CommonConfiguration的字段。

在未来，我们可能会考虑将metaStorage Plugin与ConfigService结合，将配置上报到注册中心。当我们需要此功能时，我可以着手做这个特性。

[mxsm]

LGTM