[Feature] Webhooks support

未確定任何檔案、測試或進入點。請檢視提議的中繼資料和按專案設定的 webhook，然後使用連結的 KernelCI 整合內容，與維護者釐清事件集合、驗證和傳遞行為；完成的標準應是已就發布所要求的修補程式或修補程式系列中繼資料達成共識的設計。

As part of the effort to enhance Kernel testing I am working with KernelCI to implement Patchwork support on their end (kernelci/kernelci-api#307). To make it happen I'd like to propose webhook feature for Patchwork, which will allow us to enable testing patches on KernelCI infrastructure and publish results and Patchwork checks.

I'd like to add webhook logic that will POST patch/series-related metadata [1] into specified URL from per-project webhook config [2]. Config will specify destination tree and branch, and events that should trigger the webhook.

[1] Example metadata

{
  "event": "patch-created",
  "revision": {
    "tree": "mainline",
    "url": "https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git",
    "branch": "master"
  },
  "submitter": {
        "id": 1,
        "url": "<URL>",
        "name": "John Doe",
        "email": "example@example.com"
  },
  "patches": [
    {
      "id": 1,
      "hash": "<HASH>",
      "web_url": "<URL>",
      "date": "2023-07-25T05:12:34.478Z",
      "mbox": "<URL>"
    }
  ]
}

[2] Example config

{
  "webhook": {
    "url": "<URL>",
    "auth": {
      "bearer_token": "<TOKEN>"
    }
  },
  "revision": {
    "tree": "mainline",
    "url": "https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git",
    "branch": "master"
  },
  "events": [
    "patch-created"
  ]
}

This is not finalized design and I am open to tweak any part of it to fit your requirements. Please let me know what you guys think. Thanks!