Serverless Integration: Allow modifying alarm parameters for cloudformation resources

[smelchior]

Is your feature request related to a problem? Please describe.
I am currently creating my function resources with serverless. Here the modification of alarms settings for each function works as described in the docs.
I do however also provision stepfunctions embedded directly with cloudformation code.
The alerts are generated here with the default limits, but i cannot modify them by setting metadata.

Describe the solution you'd like
I would like that the metadata passed to cloudformation resources withing serverless is checked when creating the alerts.