Adding graceful shutdown to checkout gRPC server

[kartikgola]

Changes

• This change adds graceful shutdown to checkout gRPC server by listening to OS signals.

Merge Requirements

For new features contributions, please make sure you have completed the following
essential items:

• CHANGELOG.md updated to document new feature additions
• Appropriate documentation updates in the docs
• Appropriate Helm chart updates in the helm-charts

Maintainers will not merge until the above have been completed. If you're unsure
which docs need to be changed ping the
@open-telemetry/demo-approvers.

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: kartikgola / name: Kartik Gola (5a457c2, 2dc2d76)
• ✅ login: julianocosta89 / name: Juliano Costa (4cf1431, 052c7a4)

[julianocosta89]

Thx for that @kartikgola