Improve Ruleset validation

[mnaumanali94]

To Reproduce

Use .spectral.yml:

extends: 'spectral:oas'
rules:
  se_oas3_components_must_exist:
    type: style
    given: $
    formats:
      - oas3
    message: '{{error}}'
    then:
      field: components
      function: schema
      functionOptions:
        type: object
        minItems: 1

Look at validations for spectral file.

Expected Results

I would expect one error relating to the lack of a schema object under functionOptions.

Actual Results

This made fixing a simple problem a goose chase. The CLI at least returns the actual error, though a ton of extra garbage:

$ spectral lint -r ~/Downloads/se-spectral.yml ~/Documents/Stoplight\ Studio/test/test.v1.json
/rules/se_oas3_components_must_exist/then/functionOptions should NOT have additional properties
/rules/se_oas3_components_must_exist/then/functionOptions should have required property 'schema'
/rules/se_oas3_components_must_exist/then should match "then" schema
/rules/se_oas3_components_must_exist/then should be array
/rules/se_oas3_components_must_exist/then should match some schema in anyOf
/rules/se_oas3_components_must_exist should be string
/rules/se_oas3_components_must_exist should be equal to one of the allowed values
/rules/se_oas3_components_must_exist should be boolean
/rules/se_oas3_components_must_exist should be array
/rules/se_oas3_components_must_exist should match exactly one schema in oneOf

Expected

Improve the ruleset validation to show better errors for spectral rulesets