WIP: Advanced validation proof of concept

[brennj]

Implements support for advanced validation logic and computed values in JSON Schema Forms based on RFC #39.

The main changes are:

• Adds a new x-jsf-logic extension that can contain:

  • validations - Custom validation rules defined in JsonLogic format
  • computedValues - Values computed dynamically from other fields
  • if/then/else conditional logic

• createValidationChecker utility parses schema and extracts rules into a map for efficient validation

• Properties can define x-jsf-requiredValidations to link required custom validations

• Computed values can be used in attributes like title, description, minimum etc via x-jsf-computedAttributes

• yupSchemaWithCustomJSONLogic integrates custom validations into Yup schemas

• Supports referencing nested fields in objects and arrays

• Inline rules can be defined directly in computed attributes

• Extensive test cases added covering wide range of examples

This enables much more advanced dynamic behaviour in forms based on values of other fields. Helps unify validation logic between client and server.

See the RFC internally for full details and other Remote specific examples. Main benefits are:

• Single source of truth for advanced validations
• More dynamic/adaptive behaviour
• External integrations can leverage the logic directly
• Progress towards fully defining forms in JSON

[brennj]

Closing in favour of the slew of other PRs that make it more.. digestible :D

• Part 0 const validation support in json-schema-form
• Part 1 adds the foundation of JSON logic with x-jsf-logic-validations
• Part 2 adds the groundwork for x-jsf-logic-computedAttrs
• Part 3 more advanced string template in a computedAttr
• Part 4 error handling for badly written schemas regarding x-jsf-logic-computedAttrs
• Part 5 more error handling, focus towards handling bad validations
• Part 6 inline rules on x-jsf-logic-computedAttrs
• Part 7 all of the above support, but when in an if/then/else statement.
• Part 8 same as part 7, expanding on the test suite
• Part 9 the same support, but applied to a fieldset/group array item.