feat: Support CloudFormation Join & Sub function in environment variable

[yo-ga]

Description

• Support CloudFormation the following intrinsic functions in environment variable
  • Fn::Join
  • !Join
  • Fn::Sub
  • !Sub

Motivation and Context

• Fix Using Fn::Join resolves to [Object Object] #1013
• Fix [object Object] as environment variable when using CF functions #1713

How Has This Been Tested?

example yaml:

service: aws-node-project
frameworkVersion: '3'

provider:
  name: aws
  runtime: nodejs18.x
  region: ap-northeast-1
  stage: dev
  environment:
      getKeyARN:
        Fn::Join:
          - ':'
          - - 'arn:aws:lambda'
            - ${self:provider.region}
            - Ref: 'AWS::AccountId'
            - 'function'
            - ${self:service}-${self:provider.stage}-getKey
      qa: 12345

functions:
  function1:
    handler: index.handler
    environment:
      getKeyARN:
        Fn::Join:
          - ':'
          - - 'arn:aws:lambda'
            - ${self:provider.region}
            - Ref: 'AWS::AccountId'
            - 'function'
            - ${self:service}-${self:provider.stage}-getKey
      qa: 12345

plugins:
  - serverless-offline

eample js:

module.exports.handler = async (event) => {
  console.log("test")
  console.log(process.env)
  return {
    statusCode: 200,
    body: JSON.stringify(
      {
        message: 'Go Serverless v3.0! Your function executed successfully!',
        input: event,
      },
      null,
      2
    ),
  };
};