Validate VIA and COCO files for untracked data

[sfmig]

Description

What is this PR

• Bug fix
• Addition of a new feature
• Other

Why is this PR needed?

What does this PR do?
Adds an annotations module for creating and manipulating annotations objects. This PR focuses on defining validators for input data files with bounding boxes annotations.

More specifically:

• Adds validators for input generic JSON files, VIA JSON files and COCO JSON files
  • the generic JSON file validator takes a filepath and optionally a JSON schema to validate the JSON field types.
  • the VIA and COCO JSON file validators are subclasses of the generic JSON file validator, for which the JSON schema is fixed.
• Adds test for validators

Questions

• Right now in the generic JSON validation I follow the jsonschema package, which only checks the types of keys if they are defined in the schema. That means that if none of the keys in the schema appear in the file, the validation still passes (see example below). The reason for this is simplicity. I only check if specific keys are present in the VIA and COCO files validation. Any thoughts on this? Right now I am thinking I can make it more strict later if it becomes a problem.

  E.g. the following validation passes:

   from jsonschema import validate
   
   schema = {
   	"type" : "object",
   	"properties" : {
   		"price" : {"type" : "number"},
   		"name" : {"type" : "string"},
   	},
   }
   
   validate(instance={"veggie" : "Eggs"}, schema=schema) # Passes

• I define the file-specific validators as subclasses of the JSON validator, but also make the validations in these subclasses more strict. Is this a good idea? According to this SO post this is bad practice. I think it is alright, but curious to hear other thoughts.

TODO:

• For file specific validations, add a check that verifies the schema defines types for the required keys.
  • otherwise if the schema has all keys that are not present in the input file, it will still pass the validation
• Split PR between training setup and validators

References

Please reference any existing issues/PRs that relate to this PR.

How has this PR been tested?

Please explain how any new code has been tested, and how you have ensured that no existing functionality has changed.

Is this a breaking change?

If this PR breaks any existing functionality, please explain how and why.

Does this PR require an update to the documentation?

If any features have changed, or have been added. Please explain how the
documentation has been updated.

Checklist:

• The code has been tested locally
• Tests have been added to cover all new functionality
• The documentation has been updated to reflect any changes
• The code has been formatted with pre-commit

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[sfmig]

closing because work was split into #27, #26, #28