fix: do not evaluate inputs and outputs in mappings during loadtime

[gurjotkaur20]

Fixes #939

[ghost]

I think this would not suffice the complete requirement. Consider the below workflow example which is using the same mappings object as given in the issue:

summary: Fetch user
tasks:
  - id: mysql_user_one
    fn: datasource.mysql.user.findUnique
    args: <% mappings[config.bname].user.get %>

The expectation is that mappings inputs variable should get evaluated at the workflow execution time. But here id is passed as it is. Below are the args after evaluation:

{
  "where": {
    "id": "<% inputs.params.id %>"
  },
  "select": {
    "id": true,
    "name": true,
    "email": true,
    "enabled": true,
    "roles": {
      "select": {
        "name": true
      }
    }
  },
  "bName": "bankA",
  "cName": {
    "type": "string"
  }
}

This needs re-design of the script compilation/evaluation. So keeping this issue as open for now.