Merged PR 2246: KPIs refactor: naming convention and PBI sources replication

Changing naming to follow convention.
This PR has the following changes:
- the model `int_core__mtd_aggregated_metrics` has been moved to cross and changed the name to `int_mtd_aggregated_metrics`
- the model `int_core__monthly_aggregated_metrics_history_by_deal` has been moved to cross and changed the name to `int_monthly_aggregated_metrics_history_by_deal`
- the reporting models `core__mtd_aggregated_metrics` and `core__monthly_aggregated_metrics_history_by_deal` now source the `int_mtd_aggregated_metrics` and `int_monthly_aggregated_metrics_history_by_deal` to avoid breaking the production dashboard
- the reporting models have been duplicated from core into general with the correct names, i.e., `mtd_aggregated_metrics` and `monthly_aggregated_metrics_history_by_deal`
- Documentation has been moved in intermediate and replicated in reporting, adding comments on the currently in use models that are going to die soon.

This will allow for a transition of the PBI dashboard from one source to another. Exposures file still not touched since technically the report is still sourcing the 'legacy' models. Documentation of the refactor here: https://www.notion.so/knowyourguest-superhog/Refactoring-Business-KPIs-5deb6aadddb34884ae90339402ac16e3

Related work items: #18202

models/reporting/general/mtd_aggregated_metrics.sql

@@ -0,0 +1,20 @@
+with
+    int_mtd_aggregated_metrics as (
+        select * from {{ ref("int_mtd_aggregated_metrics") }}
+    )
+
+select
+    year as year,
+    month as month,
+    day as day,
+    is_end_of_month as is_end_of_month,
+    is_current_month as is_current_month,
+    date as date,
+    previous_year_date as previous_year_date,
+    order_by as order_by,
+    number_format as number_format,
+    metric as metric,
+    value as value,
+    previous_year_value as previous_year_value,
+    relative_increment as relative_increment
+from int_mtd_aggregated_metrics