Support per-format rulesets

Is your feature request related to a problem? Please describe.

When I specify a ruleset in extends, such as recommended, it applies to all formats. I want to be able to apply recommended for OpenAPI and minimal for AsyncAPI.

Describe the solution you'd like

I'm actually not sure what would make sense here, since extends is an array. I'm open to suggestions and we should consider this alongside proposed changes in #1723 so they make sense together.

Per-format sections could work? Like the per-api sections, but different?

openapi-31:
  extends:
    - recommended
    - my-super-rules.yaml
  rules:
    security-defined: error

Describe alternatives you've considered

Changing extends completely to be an object.

extends:
  all:
    - minimal
  openapi-31:
     - recommended
  arazzo-10:
    - recommended-strict
    - spot

Another alternative:

• tell users who lint multiple formats not to use extends at all but to use the per-format rules sections and provide copy/paste versions of our built in rulesets for each format (this is the short-term solution whatever we decide)
  Additional context

From a conversation with @DmitryAnansky and @tatomyr about multi-format linting features.

No source file or test is named. Start by reviewing proposed changes in #1723 and the existing multi-format linting discussion, then trace how extends and per-format sections are currently represented. Done means an agreed, documented configuration design that supports different rulesets per format and is covered by appropriate tests.