Plots: Add the bounding boxes informations in the dvc plots diff command so that VScode can display them.

[AlexandreKempf]

Works with this DVClive PR and this VSCode PR.

DVClive is responsible for saving JSON annotation files. The annotations files have the same path as the image they match, but ends with .json.

Example:

plots/images/dogs.png
plots/images/dogs.json

Or for step images:

plots/images/cats/0.png
plots/images/cats/0.json
plots/images/cats/1.png
plots/images/cats/1.json

The JSON files have this format:

{
    "annotations": {
        "person": [
            {
                "box": {
                    "top": 1,
                    "left": 10,
                    "bottom": 30,
                    "right": 40
                },
                "score": 0.8
            }
        ],
        "dog": [
            {
                "box": {
                    "top": 200,
                    "left": 50,
                    "bottom": 240,
                    "right": 160
                },
                "score": 0.3
            },
            {
                "box": {
                    "top": 57,
                    "left": 34,
                    "bottom": 246,
                    "right": 144
                },
                "score": 0.2
            }
        ]
    }
}

After the dvc plots diff --split --json the expected output is to have the annotations alongside the image

{
  "data": {
    "plots/bounding_boxes.png": [
      {
        "type": "image",
        "revisions": [
          "workspace"
        ],
        "url": "//bounding_boxes.png",
        "annotations": {
          ... content from the json file "annotations" field should be here
        }
      }
    ]
  }
}

⚠️ Mising unit tests, I might need help on this. Tests in this repo are complicated to navigate on a first PR.

Fixes #10198

• ❗ I have followed the Contributing to DVC checklist.

• 📖 If this PR requires documentation updates, I have created a separate PR (or issue, at least) in dvc.org and linked it here.

Thank you for the contribution - we'll try to review it as soon as possible. 🙏

[dberenbaum]

@AlexandreKempf I guess the tests are still WIP?

[dberenbaum]

Can you explain a bit what's happening here?

[AlexandreKempf]

Let me know if it is clear now ;)

[mattseddon]

Needs tests

[skshetry]

Hey @mattseddon. Could you please take a look at this PR (and maybe takeover)?

[codecov]

Codecov Report

Attention: Patch coverage is 56.89655% with 25 lines in your changes are missing coverage. Please review.

Project coverage is 90.58%. Comparing base (b0384f8) to head (7b5a55a).

Files	Patch %	Lines
dvc/render/converter/image.py	59.45%	13 Missing and 2 partials ⚠️
dvc/repo/plots/__init__.py	47.36%	7 Missing and 3 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #10312      +/-   ##
==========================================
- Coverage   90.63%   90.58%   -0.06%     
==========================================
  Files         500      500              
  Lines       38626    38675      +49     
  Branches     5584     5594      +10     
==========================================
+ Hits        35010    35034      +24     
- Misses       2971     2991      +20     
- Partials      645      650       +5     

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[mattseddon]

will get back to this later