Add option to supply a parameters file in yaml, json or dot-env

[samjarrett]

in yaml/json, it should accept both "AWS format" and simplified - e.g.

AWS format:

- ParameterKey: keyname
  ParameterValue: value
- ParameterKey: anotherkeyname
  ParameterValue: secondvalue

[
  {
    "ParameterKey": "keyname",
    "ParameterValue": "value"
  },
  {
    "ParameterKey": "anotherkeyname",
    "ParameterValue": "secondvalue"
  }
]

Simplified:

keyname: value
anotherkeyname: secondvalue

{
  "keyname": "value",
  "anotherkeyname": "secondvalue"
}

dot-env would need to be only in simplified form:

keyname=value
anotherkeyname=secondvalue

it should check the template for what parameters are present, and only pass in ones that are in the template, so it doesn't error for "too many parameters"

[r2690698]

@samjarrett i have forked this and added the abilty to inject params with arug --parameter-overrides, dose the project accept PR ?

[samjarrett]

Hi @r2690698, sure. I'm happy to review it if you send it through