feat(microservices): allow grpc-server graceful shutdown

[mathieubergeron]

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• Tests for the changes have been added (for bug fixes / features)
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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?

The grpc-server always closes using forceShutdown(). That does not allow graceful shutdown of the application.

forceShutdown: Forcibly shuts down the server. The server will stop receiving new calls and cancel all pending calls.

Issue Number: #12005

What is the new behavior?

Added a gracefulShutdown option for gRPC. When set to true, grpc-server will use tryShutdown when closing instead of forceShutdown.

tryShutdown: Gracefully shuts down the server. The server will stop receiving new calls, and any pending calls will complete.

Does this PR introduce a breaking change?

• Yes
• No

Other information

GrpcOptions is shared between server-grpc and client-grpc. So technically, it is possible to set gracefulShutdown even for the client. Unfortunately, graceful shutdown does not seem currently available for the client in grpc-js (see grpc/grpc-node#1340)

[coveralls]

Pull Request Test Coverage Report for Build 2308f034-fa12-4028-8f0f-6dc6fd2ab8e0

• 8 of 8 (100.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.008%) to 92.872%

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Totals
Change from base Build c1539b00-4ddf-456c-973a-cfbbd4a2012d:	0.008%
Covered Lines:	6371
Relevant Lines:	6860

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💛 - Coveralls