Merged PR 3329: First version of KPIs refactored - created bookings

# Description

Creates skeleton for new KPIs data flow for created_bookings metric. Details are accessible [here](https://www.notion.so/knowyourguest-superhog/KPIs-Refactor-Let-s-go-daily-2024-10-23-1280446ff9c980dc87a3dc7453e95f06?pvs=4#12a0446ff9c98085bf4dfc77f6fc22f7)

In essence:
* Models are created in intermediate in a kpis folder.
* Models have a daily segmentation. This includes `created_bookings` models, but also the daily lifecycle per listing and the segmentation. It also adds a `dimension_dates` model specific for KPIs. These have all the dimensions already in place and handle all the crazy logic.
* Other time aggregation models simply read from existing daily models which are much easier (`int_kpis__metric_mtd_created_bookings` and `int_kpis__metric_monthly_created_bookings`).
* Dimensionality aggregation can be easily added within a given timeframe (daily, mtd, monthly). For instance, I do it for mtd in the `int_kpis__aggregated_mtd_created_bookings` and for monthly in `int_kpis__aggregated_monthly_created_bookings`
* Macro configuration for dimensions: Allows to set any specific dimension for `aggregated` models. By default, the subset of global, by billing country, by number of listings and by deal apply - since these are needed for Main KPIs. I added an example with Dash Source, that currently does not exist and it's currently configured as only appearing for created bookings.
* Testing `aggregated` models completeness. A new macro called `assert_dimension_completeness` is available that ensures additive metrics are consistent vs. the global result, configurable at schema level.
* Testing refactor impact. I'm aware that changing the lifecycle model to daily impacts the volumes for listing segments. For the rest, I added a `tmp` test that checks that the dimension and dimension value per date exactly match comparing new vs. old computation.

Latest edits:
* Changed naming convention
* Split of MTD and Monthly. Now these are 2 different entities, as stated in `int_kpis__dimension_dates`.
* Added start_date and end_date for models that contemplate a range (mtd, monthly).
* Added a small readme entry in the kpis folders. Mostly it states nomenclature and some first conventions.

Dbt docs:
![image (5).png](https://guardhog.visualstudio.com/4148d95f-4b6d-4205-bcff-e9c8e0d2ca65/_apis/git/repositories/54ac356f-aad7-46d2-b62c-e8c5b3bb8ebf/pullRequests/3329/attachments/image%20%285%29.png)

# Checklist

- [X] The edited models and dependants run properly with production data.
- [X] The edited models are sufficiently documented.
- [X] The edited models contain PK tests, and I've ran and passed them.
- [ ] I have checked for DRY opportunities with other models and docs. **Likely we'll be able to add macros for mtd and dim_agg models. We will see later on.**
- [ ] I've picked the right materialization for the affected models. **Models run ok except for the daily lifecycle of listings, which lasts several minutes in the first run. Model curr...

models/intermediate/kpis/int_kpis__metric_mtd_created_bookings.sql

@@ -0,0 +1,30 @@
+{{
+    config(
+        materialized="view",
+        unique_key=[
+            "end_date",
+            "id_deal",
+            "dash_source",
+            "active_accommodations_per_deal_segmentation",
+        ],
+    )
+}}
+
+select
+    -- Unique Key --
+    d.first_day_month as start_date,
+    d.date as end_date,
+    b.id_deal,
+    b.dash_source,
+    b.active_accommodations_per_deal_segmentation,
+    -- Dimensions --
+    b.main_billing_country_iso_3_per_deal,
+    -- Metrics --
+    sum(b.created_bookings) as created_bookings
+from {{ ref("int_kpis__dimension_dates") }} d
+left join
+    {{ ref("int_kpis__metric_daily_created_bookings") }} b
+    on date_trunc('month', b.date)::date = d.first_day_month
+    and extract(day from b.date) <= d.day
+where d.is_month_to_date = true and b.id_deal is not null
+group by 1, 2, 3, 4, 5, 6