Merged PR 3875: Propagates AccountType to staging

# Description

Propagates `AccountType` to staging by creating the first version of the model `stg_core__account_type`

# 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: #18944

models/staging/core/_core_sources.yml

@@ -275,3 +275,5 @@ sources:
         identifier: ScreenAndProtect
       - name: StandaloneProtection
         identifier: StandaloneProtection
+      - name: AccountType
+        identifier: AccountType

models/staging/core/schema.yml

@@ -1803,3 +1803,43 @@ models:
         description: "Timestamp of when this record was extracted into DWH."
         tests:
           - not_null
+
+  - name: stg_core__account_type
+    description: |
+      A table containing the different types of accounts created in SH backend.
+
+    columns:
+      - name: id_account_type
+        data_type: bigint
+        description: |
+          Unique identifier of the account type.
+          Acts as the primary key for this table.
+        tests:
+          - not_null
+          - unique
+
+      - name: account_type_name
+        data_type: character varying
+        description: |
+          Name of the account, in upper case, without spacing.
+          Cannot be null. Must be unique.
+        tests:
+          - not_null
+          - unique
+
+      - name: account_type_display_name
+        data_type: character varying
+        description: |
+          A more nicer way to display the name of the account, better fit 
+          for reporting purposes.
+          Cannot be null. Must be unique.
+        tests:
+          - not_null
+          - unique
+
+      - name: dwh_extracted_at_utc
+        data_type: timestamp with time zone
+        description: |
+          Timestamp of when this record was extracted into DWH.
+        tests:
+          - not_null

models/staging/core/stg_core__account_type.sql

@@ -0,0 +1,13 @@
+with
+    raw_account_type as (select * from {{ source("core", "AccountType") }}),
+    stg_core__account_type as (
+        select
+            {{ adapter.quote("Id") }} as id_account_type,
+            upper({{ adapter.quote("Name") }}) as account_type_name,
+            {{ adapter.quote("FullName") }} as account_type_display_name,
+            {{ adapter.quote("_airbyte_extracted_at") }} as dwh_extracted_at_utc
+
+        from raw_account_type
+    )
+select *
+from stg_core__account_type