feat(): enable defining global responses

[razvanz]

Enables defining global responses which are inherited by all server routes.

fixes #884

PR Checklist

Please check if your PR fulfils the following requirements:

• The commit message follows our guidelines: https://github.com/nestjs/nest/blob/master/CONTRIBUTING.md
• 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 behaviour?

Issue Number: #884

What is the new behaviour?

DocumentBuilder.addResponse has been added as a way to specify API responses globally. All server routes are then by default extending global responses.

SwaggerModule.createDocument(
  app,
  new DocumentBuilder()
    .addResponse({
      status: 500,
      description: 'Internal server error'
    }) // Same type as @ApiResponse decorator: ApiResponseOptions
   ...
)

Does this PR introduce a breaking change?

[ ] Yes
[x] No

Other information

[woodcockjosh]

@razvanz can you fix the merge conflicts. Would love to have this.

[cooperate]

Any updates on this? Has this been resolved already?

[cooperate]

I made my own PR with the merge conflicts resolved FWIW.
#1287

[kamilmysliwiec]

Closing as this PR seems to be stale

[woodcockjosh]

Please reopen this. I would really like to have this feature. It only got stale because no one ever merged it.

[kamilmysliwiec]

If you're interested in creating a PR that uses this PR + resolves conflicts, that would be great! Contributions are more than welcome