Merged PR 4504: Onboarding MRR + Visualisation changes

# Description

Changes:
* Adds Onboarding MRR
* Refactors exclusion code for ongoing month / invoicing cycle
* Adds sign format on relative differences

# 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.
- [X] I have checked for DRY opportunities with other models and docs.
- [X] 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: #27609, #27805

models/intermediate/cross/int_ytd_mtd_main_metrics_overview.sql

@@ -40,6 +40,7 @@ with
             as current_month_mtd_total_revenue_churn_12m,
             total_revenue_global_preceding_12_months
             as current_month_mtd_total_revenue_global_12m,
+            expected_mrr as current_month_mtd_onboarding_mrr,
 
             -- Previous Year (12 months ago), Month To Date Metrics --
             previous_year_total_revenue_in_gbp
@@ -66,6 +67,7 @@ with
             as previous_year_mtd_total_revenue_churn_12m,
             previous_year_total_revenue_global_preceding_12_months
             as previous_year_mtd_total_revenue_global_12m,
+            previous_year_expected_mrr as previous_year_mtd_onboarding_mrr,
 
             -- Previous Month, End Of Month Metrics --
             lag(total_revenue_in_gbp) over (
@@ -109,7 +111,10 @@ with
             ) as previous_month_eom_total_revenue_churn_12m,
             lag(total_revenue_global_preceding_12_months) over (
                 partition by dimension, dimension_value order by date
-            ) as previous_month_eom_total_revenue_global_12m
+            ) as previous_month_eom_total_revenue_global_12m,
+            lag(expected_mrr) over (
+                partition by dimension, dimension_value order by date
+            ) as previous_month_eom_onboarding_mrr
 
         from int_mtd_vs_previous_year_metrics
         where
@@ -188,6 +193,11 @@ with
                 order by date
                 rows between unbounded preceding and current row
             ) as current_ytd_total_revenue_global_12m,
+            sum(current_month_mtd_onboarding_mrr) over (
+                partition by financial_year, dimension, dimension_value
+                order by date
+                rows between unbounded preceding and current row
+            ) as current_ytd_onboarding_mrr,
             -- Specific treatment for live_deals as it is a counter
             current_month_mtd_live_deals as current_ytd_live_deals,
 
@@ -257,6 +267,11 @@ with
                 order by date
                 rows between unbounded preceding and current row
             ) as previous_ytd_total_revenue_global_12m,
+            sum(previous_year_mtd_onboarding_mrr) over (
+                partition by financial_year, dimension, dimension_value
+                order by date
+                rows between unbounded preceding and current row
+            ) as previous_ytd_onboarding_mrr,
             -- Specific treatment for live_deals as it is a counter
             previous_year_mtd_live_deals as previous_ytd_live_deals