Merged PR 3373: Setting current KPIs models for deprecation

# Description

Sets up warning for KPIs models that will be deprecated, which are:
* 13 in core
* 2 in xero
* 5 in cross

I will keep alive the cross models that handle the final aggregations for Main KPIs for the time being, as well as the newly created Churn model that has a dependency on the monthly by deal to be filled into the mtd flow. I think handling exposure logic for Main KPIs could be a separated migration.

In other words, this is already quite a bit to migrate.

# Checklist

 **I just checked that dbt compiles correctly**

- [NA] The edited models and dependants run properly with production data.
- [NA] The edited models are sufficiently documented.
- [NA] The edited models contain PK tests, and I've ran and passed them.
- [NA] I have checked for DRY opportunities with other models and docs.
- [NA] I've picked the right materialization for the affected models.

# Other

- [ ] Check if a full-refresh is required after this PR is merged.

Related work items: #23268

models/intermediate/cross/schema.yml

@@ -189,6 +189,8 @@ models:
       - 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.
 
+    deprecation_date: 2024-11-30
+
     columns:
       - name: year
         data_type: int
@@ -244,6 +246,8 @@ models:
       This model provides the necessary dates for each deal for deal-based KPIs models to work.
       It only considers those dates starting from when the host user of the deal was first available.
 
+    deprecation_date: 2024-11-30
+
     tests:
       - dbt_utils.unique_combination_of_columns:
           combination_of_columns:
@@ -518,6 +522,8 @@ models:
       ... and so on and forth for any available dimension. These combinations should appear
       for each date of the MTD models.
 
+    deprecation_date: 2024-11-30
+
     tests:
       - dbt_utils.unique_combination_of_columns:
           combination_of_columns:
@@ -1444,6 +1450,8 @@ models:
         this happens likely because of misconfiguration between Hubspot and Core. This should be reported to increase 
         data quality.
 
+    deprecation_date: 2024-11-30
+
     tests:
       - dbt_utils.unique_combination_of_columns:
           combination_of_columns:
@@ -1534,6 +1542,8 @@ models:
       It's used for the business KPIs. Data is aggregated at the last day of the month and in the
       days necessary for the Month-to-Date computation of the current month.
 
+    deprecation_date: 2024-11-30
+
     tests:
       - dbt_utils.unique_combination_of_columns:
           combination_of_columns: