support same format for codepipeline cloudformation config as cloudformation --cli-input-json

[hauntingEcho]

Is your feature request related to a problem? Please describe.
Currently, the format expected by codepipeline for cloudformation config differs slightly from the format used by --cli-input-json for aws cloudformation update-stack and aws cloudformation create-stack. Specifically, tags are expressed as a map for codepipeline and a list of objects with key and value properties for aws cloudformation. This means users must maintain two versions of each configuration, if they want to be able to use both tools.

Describe the solution you'd like
Both ways of configuring the cloudformation template support a shared format. It doesn't really matter which, although I tend to prefer the way codepipeline is doing tags.

Describe alternatives you've considered
Since codepipeline requires a raw file, any automated translation tool would need to go from the codepipeline format to the aws cloudformation format. However, we haven't yet hit the point where maintaining such a tool is simpler than maintaining two copies of every config file.

Additional context
output of aws cloudformation create-stack --generate-cli-skeleton:

{
    "StackName": "",
    "TemplateBody": "",
    "TemplateURL": "",
    "Parameters": [
        {
            "ParameterKey": "",
            "ParameterValue": "",
            "UsePreviousValue": true,
            "ResolvedValue": ""
        }
    ],
    "DisableRollback": true,
    "RollbackConfiguration": {
        "RollbackTriggers": [
            {
                "Arn": "",
                "Type": ""
            }
        ],
        "MonitoringTimeInMinutes": 0
    },
    "TimeoutInMinutes": 0,
    "NotificationARNs": [
        ""
    ],
    "Capabilities": [
        "CAPABILITY_AUTO_EXPAND"
    ],
    "ResourceTypes": [
        ""
    ],
    "RoleARN": "",
    "OnFailure": "DO_NOTHING",
    "StackPolicyBody": "",
    "StackPolicyURL": "",
    "Tags": [
        {
            "Key": "",
            "Value": ""
        }
    ],
    "ClientRequestToken": "",
    "EnableTerminationProtection": true
}

[hauntingEcho]

Closing this as I'm pretty sure that what I actually need is #2828