Add JSON schema validation for Context Data

[TribuneX]

NetBox version

v4.3.0

Feature type

New functionality

Proposed functionality

Similar to the proposal outline in #19025 it would be really useful if a user could specify a json schema along with a config context entry.

Use case

The structure of config context can be crucial for consuming systems (e.g. automated provisioning). We currently implement JSON schema validation with custom validation. However, it is always difficult to identify which config context a certain validation should be applied to.

Being able to assign a schema directly to a config context entry would remove that complexity.

Database changes

Add an optional schema JSONField to the Config Context data model.

External dependencies

jsonschema for implementing the validation in the backend

[jeremystretch]

Somewhat related to FR #19025

[jeremystretch]

Add an optional schema JSONField to the Config Context data model.

Rather than adding a schema definition field directly on the ConfigContext model, which would be of limited utility, I've introduced a new ConfigContextProfile model to hold the schema definition. This allows it to be reused, and separates its definition from the data it validates.