feat(wren-ai-service): relationships recommendation pipeline to produce the relationships for users easily establish

[paopa]

This PR introduces the RelationshipRecommendation service and corresponding router, which provide endpoints for generating and retrieving relationship recommendations based on Model Definition Language (MDL) input.

Important

This PR based on #716, thus before it to be merged, dont merge this PR. thanks!

Web API Specification

1. Generate Relationship Recommendation

Endpoint: POST /v1/relationship-recommendations

Request Body:

{
    "mdl": "{ ... }"  // JSON string of the MDL (Model Definition Language)
}

Response:

{
    "id": "unique-uuid"
}

2. Retrieve Relationship Recommendation

Endpoint: GET /v1/relationship-recommendations/{id}

Path Parameter:

• id: Unique identifier of the relationship recommendation resource

Response:

{
   "id":"unique-uuid",
   "status":"generating", // "finished" "failed"
   "response":{
      "recommendations":[
         {
            "name":"name",
            "models":["model1", "model2"],
            "reason":"the reason why suggest this",
            "joinType":"ONE_TO_MANY",
            "condition":"..."
         }
      ]
   },
   "error":{
      "code":"OTHERS",
      "message":"Error description""failed"
   }
}

Usage

1. Call the POST endpoint to initiate a relationship recommendation generation.
2. Use the returned ID to poll the GET endpoint until the status is "finished" or "failed".
3. Once finished, retrieve the generated recommendations from the "response" field.

Notes

• The generation process is asynchronous and may take some time. Implement appropriate polling intervals when checking the status.
• Error handling has been implemented to catch and report various exceptions that may occur during the process.

Screenshots

[cyyeh]

basically LGTM, thanks for hard work.