Pre-compile HAR schema for validation

Ajv is currently used in httpsnippet for validating the HAR schema passed. Using complete Ajv dependency makes httpsnippet require 'unsafe-eval in the CSP policy, which is a security concern. (https://github.com/ajv-validator/ajv/blob/c3e203c2696e42ec107fe6a5a659fca54b2e4993/docs/security.md#content-security-policy).

As a workaround, since the schema for HAR is known (and already included), it can be pre-compiled into a validation function as part of the build. The Ajv Docs have details on the same.

This would move Ajv from a runtime dependency to a optional developer-dependency (as Ajv-cli) - only needed when har-schema is updated. This would bring a lot more benefits, including performance and bundle size improvements.

This request comes via the Stoplight Elements project, which uses httpsnippet internally. Since httpsnippet doesn't offer a way to pre-compile schemas, this ends up breaking Elements in configurations which limit unsafe-eval via CSP.

Commencez par src/helpers/har-validator.ts et examinez comment le schéma HAR inclus est actuellement validé. Consultez les indications de Ajv CLI concernant compile-schemas ainsi que la configuration de build du dépôt afin d’identifier où le code de validation généré doit être placé. Le travail est terminé lorsque la validation ne nécessite plus Ajv à l’exécution ni unsafe-eval, qu’Ajv est uniquement une dépendance de développement facultative et que les tests de validation existants passent.