service: Allow passing an application-service_name pair as a parameter

[thgreasi]

Resolves: #1361 Change-type: minor See: https://balena.zulipchat.com/#narrow/stream/346007-balena-io.2FbalenaCloud/topic/Using.20serviceName.20as.20param.20for.20service.20var.20methods.20in.20SDK

Resolves: # HQ: See: Depends-on: Change-type: major|minor|patch

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Contributor checklist

• [ ] Includes tests
• [ ] Includes typings
• [ ] Includes updated documentation
• [ ] Includes updated build output

[thgreasi]

I self-certify!