Merged PR 2003: Business KPIs first draft

This PR aims to provide a first draft for business KPIs, at this stage **quite minimal**.

It mostly contains a MTD and Monthly display approach. No dimensions are created.

The models created are:
- **int_dates_mtd**: mainly it reads from int_dates to retrieve those days needed for a MTD/monthly display
- **int_core__mtd_booking_metrics**: it contains the booking metrics, ending in a format of date|value|value last year|increment
--> here we could add, in the future, additional metrics from other sources (ex: guest journey, etc)
- **int_core__mtd_aggregated_metrics**: it transforms the data coming from the different mtd intermediate sources to be easily displayed in the dashboard. This is a good candidate for macros :)
- **core__mtd_aggregated_metrics**: copy-paste of the its int_core version, including a bit of model documentation

The dashboard is functional but in another PR. I can show you how it looks like at the moment you are going to check the PR

Related work items: #17214

models/intermediate/int_dates_mtd.sql

@@ -0,0 +1,57 @@
+/*
+This model provides Month-To-Date (MTD) necessary dates for MTD-based models to work.
+- For month-to-month complete information, it retrieves all end month dates that have elapsed since 2020.
+- For month-to-date information, it retrieves the days of the current month of this year up to yesterday. 
+  Additionally, it also gets the days of its equivalent month from last year previous the current day of month of today.
+
+Example:
+Imagine we have are at 4th June 2024.
+- We will get the dates for 1st, 2nd, 3rd of June 2024.
+- We will also get the dates for 1st, 2nd, 3rd of June 2023.
+- We will get all end of months from 2020 to yesterday, 
+  i.e., 31st January 2020, 29th February 2020, ..., 30th April 2024, 31st May 2024.
+
+*/
+with
+    int_dates as (select * from {{ ref("int_dates") }} where date_day >= {{ var("start_date") }}),
+    raw_dates as (
+        select
+            id.year_number as year,
+            id.month_of_year as month,
+            id.day_of_month as day,
+            id.date_day as date,
+            id.month_start_date as first_day_month,
+            id.month_end_date as last_day_month,
+            now()::date as today
+        from int_dates id
+    )
+-- Dates keeps only end of month (EOM) dates, as well as
+-- dates corresponding to the current month and the same month last year
+select distinct
+    rd.year,
+    rd.month,
+    rd.day,
+    rd.date,
+    rd.first_day_month,
+    rd.last_day_month,
+    case when rd.date = rd.last_day_month then 1 else 0 end as is_end_of_month,
+    case
+        when date_trunc('month', rd.date) = date_trunc('month', rd.today) then 1 else 0
+    end as is_current_month
+from raw_dates rd
+where
+    rd.today > rd.date
+    -- include only up-to yesterday
+    and (
+        rd.date = rd.last_day_month
+        -- keep all last day of the month
+        or rd.date >= date_trunc('month', rd.today)
+        -- keep all individual days of the current month
+        or (
+            rd.year = extract(year from rd.today) - 1
+            and rd.month = extract(month from rd.today)
+            and rd.day < extract(day from rd.today)
+        )
+    -- keep all days of same month last day up to yesterday's day
+    )
+