feat: add support for multiple authentication types

[nean]

PR Checklist

Please check if your PR fulfills 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 behavior?

The current api only allows for combining security requirements using logical OR. OpenApi specification also supports combining security requirements using logical AND.
https://swagger.io/docs/specification/authentication/

@ApiSecurity('key1')
@ApiSecurity('key2')
@Controller('cats')
class CatsController {}

{
  "security": [
    { "key1": [] },
    { "key2": [] }
  ]
}

Issue Number: #130

What is the new behavior?

@ApiSecurity({ key1: [], key2: []})
@Controller('cats')
class CatsController {}

{
  "security": [
    { "key1": [] , "key2": [] }
  ]
}

Does this PR introduce a breaking change?

[ ] Yes
[x] No

[kamilmysliwiec]

LGTM