feat(swagger): JSON and YAML document endpoints customizable

[jcolladosp]

PR Checklist

Please check if your PR fulfills the following requirements:

• [X] The commit message follows our guidelines: https://github.com/nestjs/nest/blob/master/CONTRIBUTING.md
• [X] Tests for the changes have been added (for bug fixes / features)
• [ ] Docs have been added / updated (for bug fixes / features)

PR Type

What kind of change does this PR introduce?

• [ ] Bugfix
• [X] Feature
• [ ] Code style update (formatting, local variables)
• [ ] Refactoring (no functional changes, no api changes)
• [ ] Build related changes
• [ ] CI related changes
• [ ] Other... Please describe:

What is the current behavior?

Right now the swagger json and yam are deployed in ${finalPath}-json and ${finalPath}-yaml, without possibility of customization:

http://localhost:3000/api-json
http://localhost:3000/api-yaml

Issue Number: #1968

What is the new behavior?

Added the options jsonDocumentUrl and yamlDocumentUrl in the interface SwaggerCustomOptions If the option value is present, json and/or yaml documents are served in the specified url. Furthermore, if globalPrefix is specified in the nest options, it's used as prefix for the custom urls.

Does this PR introduce a breaking change?

• [ ] Yes
• [X] No

Other information