Redocly Lint Support

Hi i would like to create support for [redocly cli](https://redocly.com/docs/cli/commands/lint/) as a linter for openapi. I'm more than happy to take this work on if someone can point me in the correct direction or mentor me for this. I'm keen on adding this here as i'm already using spotless and don't want to create a one off gradle plugin and need to manage npm installs.

Start with the Redocly CLI lint documentation linked in the issue, then inspect Spotless's existing linter integration points. The finished work should add Redocly CLI as an OpenAPI linter usable through Spotless, without requiring a separate Gradle plugin or separately managed npm installation.

Written by the indexing model from the issue text.