feat(microservices): grpc package name can be specified with service name

[JadenKim-dev]

PR Checklist

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• 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
• 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?

Issue Number: #13719

If there are gRPC services with duplicate names, it is not possible to register handlers separately even if they are distinguished by different packages.

What is the new behavior?

In decorators like @GrpcMethod, specifying the service name like package.MethodName allows handlers to be registered for each package separately.

Does this PR introduce a breaking change?

• Yes
• No

Other information

[coveralls]

Pull Request Test Coverage Report for Build 793707e2-04d1-4ccc-919f-9801d0933acd

Details

• 10 of 10 (100.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.003%) to 92.21%

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Totals
Change from base Build 0f9b0016-1853-4775-8f4d-a4d89fc35f0f:	0.003%
Covered Lines:	6747
Relevant Lines:	7317

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💛 - Coveralls

[coveralls]

Pull Request Test Coverage Report for Build 2785b6f3-f183-43bc-8a6c-a51dceb9710a

Details

• 10 of 10 (100.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.003%) to 92.21%

---

Totals
Change from base Build 0f9b0016-1853-4775-8f4d-a4d89fc35f0f:	0.003%
Covered Lines:	6747
Relevant Lines:	7317

---

💛 - Coveralls

[kamilmysliwiec]

lgtm