[SAM] Parameterize template.yaml to split prod/stage environments.

[binchoo]

Create a Env parameter

Parameters:
  Env:
    Type: String
    AllowedValues: 
       - prod
       - test

Create a IsProd condition

Conditions:
  IsProd: !Equals
    - !Ref Env
    - prod

Use the !If intrinsic function to configure differently per environment

Resources:
  PaimonGanyuSpringBootApp:
    Type: AWS::Serverless::Function
    Properties:
      …
      ProvisionedConcurrencyConfig:
        ProvisionedConcurrentExecutions: !If [IsProd, 3, 1]
      DeploymentPreference:
        Type: AllAtOnce