Verified queries implementation

[joachimhodana]

Currently, the setup for verified queries is tricky and undocumented. This PR introduces an easier way to configure verified queries via a config macro, without breaking the existing with extension (CA = '{...}') workaround.

Example:

{{ config(
    materialized='semantic_view',
    verified_queries=[
      {
        "name": "Orders by day",
        "question": "How many orders did we have each day last month?",
        "sql": "select order_date, count(*) as orders from __orders group by order_date"
      },
      {
        "name": "Revenue by month",
        "question": "What is total revenue by month?",
        "sql": "select month, sum(revenue) as total_revenue from __orders_by_month group by month"
      }
    ]
) }}

TABLES(orders as {{ ref('orders') }})
DIMENSIONS(orders.order_date, orders.month)
METRICS(orders.total_revenue as sum(orders.revenue))

NOTE:
Unfortunately, I do not have access to a personal Snowflake account to test this PR. I would appreciate it if someone could test it and confirm whether it passes the test cases.