http_*: add a HTTP API to list changefeed info (#1917)

[ti-chi-bot]

This is an automated cherry-pick of #1917

What problem does this PR solve?

#1869

What is changed and how it works?

Add a HTTP API to list changefeed info.
Add a HTTP API to check the health of CDC server. (It only return a response with 200 OK and empty body.)

Check List

Tests

• Manual test (add detailed scripts or steps below)

1. list default changefeeds

$ curl -X GET http://127.0.0.1:8300/api/v1/changefeeds
[
 {
  "id": "changefeed-test-1",
  "state": "normal",
  "tso": 425364256174112775,
  "checkpoint": "2021-06-02 20:11:04.922",
  "error": null
 },
 {
  "id": "test1",
  "state": "normal",
  "tso": 425364256174112775,
  "checkpoint": "2021-06-02 20:11:04.922",
  "error": null
 }
]

2. list all changefeeds.

$ curl -X GET http://127.0.0.1:8300/api/v1/changefeeds?state=all
[
 {
  "id": "changefeed-test-1",
  "state": "normal",
  "tso": 425364263569195009,
  "checkpoint": "2021-06-02 20:11:33.132",
  "error": null
 },
 {
  "id": "test1",
  "state": "normal",
  "tso": 425364263569195009,
  "checkpoint": "2021-06-02 20:11:33.132",
  "error": null
 },
 {
  "id": "test2",
  "state": "removed",
  "tso": 425364254063853571,
  "checkpoint": "2021-06-02 20:10:56.872",
  "error": null
 }
]

3. list normal / stopped / removed changefeed

$ curl -X GET http://127.0.0.1:8300/api/v1/changefeeds?state=normal

[
 {
  "id": "test1",
  "state": "normal",
  "checkpoint-tso": 425413530255884289,
  "checkpoint-time": "2021-06-05 00:23:50.627",
  "error": null
 },
 {
  "id": "test2",
  "state": "normal",
  "checkpoint-tso": 425413530255884289,
  "checkpoint-time": "2021-06-05 00:23:50.627",
  "error": null
 }
]

$ curl -X GET http://127.0.0.1:8300/api/v1/changefeeds?state=stopped

[
 {
  "id": "test4",
  "state": "stopped",
  "checkpoint-tso": 425412960562708481,
  "checkpoint-time": "2021-06-04 23:47:37.420",
  "error": null
 }
]

$ curl -X GET http://127.0.0.1:8300/api/v1/changefeeds?state=removed

[
 {
  "id": "test3",
  "state": "removed",
  "checkpoint-tso": 425412963750903809,
  "checkpoint-time": "2021-06-04 23:47:49.582",
  "error": null
 }

4. test POST method

$ curl -POST http://127.0.0.1:8300/api/v1/changefeeds

{
 "error": "this api supports GET method only",
 "errorCode": "CDC:ErrSupportGetOnly"
}

5. check health of CDC server

$ curl -I -X GET  http://127.0.0.1:8300/api/v1/health

HTTP/1.1 200 OK
Date: Fri, 04 Jun 2021 04:05:56 GMT
Content-Length: 0

Code changes

• Has exported function/method change

Side effects

• None

Related changes

• Need to cherry-pick to the release branch
• Need to update the documentation

Release note

• No release note

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• amyangfei

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[amyangfei]

/merge

[ti-chi-bot]

This pull request has been accepted and is ready to merge.

Commit hash: 607f241

[purelind]

/run-all-tests

[amyangfei]

/run-leak-tests

[amyangfei]

/run-integration-tests
/run-kafka-tests

[amyangfei]

/run-all-tests

[amyangfei]

/run-all-tests

[amyangfei]

This should not be cherry picked to release-4.0, PTAL @asddongmen

[amyangfei]

/merge

[amyangfei]

/run-leak-tests