curve tools v2 support export monitor target

[SeanHai]

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Is your feature request related to a problem? (你需要的功能是否与某个问题有关?)

Add a command like 'curve bs target' which will export all the target in cluster and used by monitor.
The cluster targets are endpoint of services and client. The tools need get endpoint of all the service and client form mds or service metric.
The output format is like

[
   {
      "labels" : {
         "job" : "etcd"
      },
      "targets" : [
         "127.0.0.1:2379",
         "127.0.0.2:2379",
         "127.0.0.3:2379"
      ]
   },
   {
      "labels" : {
         "job" : "mds"
      },
      "targets" : [
         "127.0.0.1:6666",
         "127.0.0.2:6666",
         "127.0.0.3:6666"
      ]
   },
   {
      "labels" : {
         "job" : "chunkserver"
      },
      "targets" : [
         "127.0.0.1:8200",
         "127.0.0.1:8201",
         "127.0.0.1:8202",
         "127.0.0.2:8200",
         "127.0.0.2:8201",
         "127.0.0.2:8202",
         "127.0.0.3:8200",
         "127.0.0.3:8201",
         "127.0.0.3:8202"
      ]
   },
   {
      "labels" : {
         "job" : "snapshotcloneserver"
      },
      "targets" : [
         "127.0.0.1:8081",
         "127.0.0.2:8081",
         "127.0.0.3:8081"
      ]
   },
   {
      "labels" : {
         "job" : "client"
      },
      "targets" : [
         "127.0.0.4:9000",
         "127.0.0.4:9001",
         "127.0.0.4:9002",
         "127.0.0.4:9003",
         "127.0.0.4:9004",
         "127.0.0.4:9005",
         "127.0.0.4:9006",
         "127.0.0.4:9007",
         "127.0.0.4:9008",
         "127.0.0.4:9009"
      ]
   }
]

Describe the solution you'd like (描述你期望的解决方法)

Describe alternatives you've considered (描述你想到的折衷方案)

Additional context/screenshots (更多上下文/截图)

Registration procedure

Step 1. Add a comment when you sign up.The purpose of comments is for us to understand you and determine whether you have the basic ability to complete this issue.

• If you are a student, please introduce your school, major, programming language, technical fields of interest, what you are good at, and why you chose this issue.
• If you are already working, please introduce your company, career, work content, technical fields of interest, and why you chose this issue.

Step 2. Use WeChat to add the Curve community assistant "Curve" as a WeChat friend, tell your GitHub ID, and send the Issue link of your choice. The assistant will invite you to communicate with the mentor by WeChat.

Step 3. In order to better complete each development task, the mentor will select the developer who best matches the issue based on everyone's comment on GitHub and communication status by WeChat. If you are not selected, please select another issue.

Tips

• Before developing, please read the dev guideline( https://ask.opencurve.io/t/topic/201) carefully and communicate with your mentor.
• Please submit a draft PR before 11.29, and the mentor will review it within 2-5 working days and may guide you to modify the PR based on the actual situation.
• If you successfully merge into PR before 12.27 and you will receive gifts carefully prepared by the Curve community.

[wsehjk]

Hello,i wanna solve this issue, please assign this to me, thanks

[Subzeroo7]

Hello,i wanna solve this issue, please assign this to me, thanks

Please add the comment according to the rules：

• If you are a student, please introduce your school, major, programming language, technical fields of interest, what you are good at, and why you chose this issue.
• If you are already working, please introduce your company, career, work content, technical fields of interest, and why you chose this issue.