feat: Support named export

[derek10cloud]

Description

This PR enhances the export functionality in StackQL to allow for named exports when reusing an .iql file for multiple resources within a stack. #41

The changes enable exports to be defined as either a simple list of strings or as objects that map exported variables to renamed assigned variables.

I also add the logic of checking type consistency in expected_exports (all items({items}) must be either dicts or non-dicts)

Fixes

• Fix the base.py file in cmd dir and the utils.py file in lib dir.
• Suppose that expected_exports's type can be a list or an object(dict)(But don't the elements of expected_exports should be same type, not allowing different type.)
• If expected_exports is an object(dict), the value of expected_exports is a name of export.

Checklist

Please make sure that the following criteria are met:

• The PR title is descriptive.
• For example stacks, I have included a descriptive README.md in the example project directory, which describes the stack and includes instructions to deploy or test.
• For example stacks, add your stack to the website template library at website/docs/template-library/.. which gets published to stackql-deploy.io (optional)
• I have ⭐'ed the stackql and stackql-deploy repos.

Additional Notes

I tested it like below

1) make stackql manifest

# will make an example of stackql resources(vpc) for aws
$ stackql-deploy init {STACK_DIR} --provider aws 
$ cd {STACK_DIR}

2) set all exports as named export (unnamed export is already supported, so I am not showing that case.)

...
    exports:
      - vpc_id: renamed_vpc_id
      - vpc_cidr_block: renamed_vpc_cidr_block
...

fyi) not allowing below manifest

...
    exports:
      - vpc_id: renamed_vpc_id
      - vpc_cidr_block 
...

becuase exports' types are different each other.

3) build resources

$ stackql-deploy build . dev -e AWS_REGION=ap-northeast-2

4) I also tested test command

$ stackql-deploy test . dev -e AWS_REGION=ap-northeast-2

5) also tested teardown command

• before test teardown, if you used named export like above, not a unnamed export, you should set props like below.

# stackql_manifest.yml
...
props:
     - name: vpc_id # populate `renamed_vpc_id` key in the context when tearing down
         value: "{{ renamed_vpc_id }}"
     - name: vpc_cidr_block # populate `renamed_vpc_cidr_block` key in the context when tearing down
        value: "{{ renamed_vpc_cidr_block }}"
    exports:
      - vpc_id: renamed_vpc_id
      - vpc_cidr_block: renamed_vpc_cidr_block

• And then execute below command

$ stackql-deploy teardown . dev -e AWS_REGION=ap-northeast-2

[derek10cloud]

fyi) my example manifest file

#
# aws starter project manifest file, add and update values as needed
#
version: 1
name: "derek-aws-vpc"
description: description for "derek-aws-vpc"
providers:
  - aws
globals:
  - name: region
    description: aws region
    value: "{{ AWS_REGION }}"
  - name: global_tags
    value:
      - Key: Provisioner
        Value: stackql
      - Key: StackName
        Value: "{{ stack_name }}"
      - Key: StackEnv
        Value: "{{ stack_env }}"
resources:
  - name: example_vpc
    description: example vpc resource
    props:
      - name: vpc_cidr_block
        values:
          prd:
            value: "10.0.0.0/16"
          sit:
            value: "10.1.0.0/16"
          dev:
            value: "10.2.0.0/16"
      - name: vpc_tags
        value:
          - Key: Name
            Value: "{{ stack_name }}-{{ stack_env }}-vpc"
        merge: ['global_tags']
      - name: vpc_id # blank when building, populate when tearing down
        value: "{{ renamed_vpc_id }}"
    exports:
      - vpc_id: renamed_vpc_id
      - vpc_cidr_block: renamed_vpc_cidr_block