feat: adds validation logic with model load and initial validation logic

[jpower432]

Description

Adds option to validate when loading a model from an io.Reader. A noop validation is added for testing or when skipping validation is desired. A schema validator is added for validation against the OSCAL JSON schemas.

Rationale

The implemented validation logic is meant to be a post-decoding semantic validation of the models where a validation interface is added. The goal is to allow customized validation including combined validations before after decoding and before encoding. Adding the schema validation after unmarshaling to a struct has some performance overhead because of the requirement to encode back to JSON for validation against the schema.

Implementation for schema validation on raw JSON before decoding with this solution

With this solution the schema validation can still be done before load using a solution like the following with the underlying go-oscal validator

	data, err := os.ReadFile("catalog.json")
	if err != nil {
		return err
	}

	validator, err := oscalValidation.NewValidator(data)
	if err != nil {
		return err
	}

	err = validator.Validate()
	if err != nil {
		return err
	}

	byteReader := bytes.NewReader(data)
	

	// Replace noop validation with future semantic validation of choice
	definition, err := models.NewComponentDefinition(byteReader, validation.NoopValidator{})
	if err != nil {
		return err
	}

Fixes #40

Will need rebase after #36 merge

How has this been tested?

• Unit tests added

Types of changes

• Hot fix (emergency fix and release)
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Documentation (change which affects the documentation site)
• Breaking change (fix or feature that would cause existing functionality to change)

Quality assurance (all should be covered).

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing tests pass locally with my changes
• All commits are signed-off.