dashboard: export full bug info

[a-nogikh]

Please do not review it yet

We get requests from the researchers community to make our data more accessible. This is a dirty and hacky version of the code that exports all published syzbot bugs as a big .tar.gz archive. It should already give some initial useful version to iterate on later.

In the final solution, this will not be an HTTP endpoint, but rather a cron command that would upload the archive to GCS. OK, AppEngine does not let us dynamically generate responses bigger than 32 MB, so I added a simple code that saves the file to a bucket.

There are a lot of TODOs before we can upstream it.

[dvyukov]

It would be good to have a test that ensures that export respects access rules within namespace and don't export bugs from other namespaces.

[tarasmadan]

With high probability https://github.com/google/syzkaller/tree/master/tools/syz-db-export already has what you need.

[tarasmadan]

Single json copy-paste:

{
  "version": 1,
  "title": "possible deadlock in bch2_trans_begin",
  "id": "0a0ae06f3db3b6fe0ab48c51aeda855cdba2403d",
  "discussions": [
    "https://groups.google.com/d/msgid/syzkaller-bugs/678db48f.050a0220.303755.0065.GAE@google.com"
  ],
  "crashes": [
    {
      "title": "possible deadlock in bch2_trans_begin",
      "kernel-config": "/text?tag=KernelConfig&x=2a31f7155996562",
      "kernel-source-git": "https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/log/?id=8560697b23dc2f405cb463af2b17256a9888129d",
      "kernel-source-commit": "8560697b23dc2f405cb463af2b17256a9888129d",
      "syzkaller-git": "https://github.com/google/syzkaller/commits/2a20f901dbd7922a27b5625a8a442587c8c3df2c",
      "syzkaller-commit": "2a20f901dbd7922a27b5625a8a442587c8c3df2c",
      "crash-report-link": "/text?tag=CrashReport&x=13a5863f980000"
    },
    {
      "title": "possible deadlock in bch2_trans_begin",
      "kernel-config": "/text?tag=KernelConfig&x=aadf89e2f6db86cc",
      "kernel-source-git": "https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/log/?id=619f0b6fad524f08d493a98d55bac9ab8895e3a6",
      "kernel-source-commit": "619f0b6fad524f08d493a98d55bac9ab8895e3a6",
      "syzkaller-git": "https://github.com/google/syzkaller/commits/968edaf491504462b98e794257533160d7087792",
      "syzkaller-commit": "968edaf491504462b98e794257533160d7087792",
      "crash-report-link": "/text?tag=CrashReport&x=15adc1f8580000"
    }
  ]
}