Deploy alerts separately from main stack

[chippyash]

This is a Feature Proposal

Description

For feature proposals:
As a systems engineer I want to be able to redeploy the alerts separately to the main stack without redeploying the main stack, so that I can amend just the alerts without causing issues with my main stack

Real world example: We've implemented this plugin with a standard base configuration in a separate Git repo. The repo is included as a Git submodule in dependent services, and included in the main stack thus:

alerts: ${file(./serverless/alerts/alerts.yml)}

We always deploy as a separate stack. It works well. However, to redeploy any changes to the alerts base sub system currently means that we have redeploy the entire service. We have a lot of services! It would be cleaner and safer to just to be able to redeploy the alerts with an sls deployment flag such as --alertsOnly

Additional Data

• Serverless Framework Version: V3

I am not a javascript dev by any means but know enough to be dangerous. I'd be happy to have a go at implementing this if someone could point me in the right direction and hold hands if required.