feat: Add currency module and remove currency models from region and pricing modules (#6536)

What:
- Creates a new currency module
- Removes currency model from the pricing module
- Removes currency model from region module

packages/pricing/src/migrations/.snapshot-medusa-pricing.json

@@ -4,61 +4,6 @@
   ],
   "name": "public",
   "tables": [
-    {
-      "columns": {
-        "code": {
-          "name": "code",
-          "type": "text",
-          "unsigned": false,
-          "autoincrement": false,
-          "primary": false,
-          "nullable": false,
-          "mappedType": "text"
-        },
-        "symbol": {
-          "name": "symbol",
-          "type": "text",
-          "unsigned": false,
-          "autoincrement": false,
-          "primary": false,
-          "nullable": false,
-          "mappedType": "text"
-        },
-        "symbol_native": {
-          "name": "symbol_native",
-          "type": "text",
-          "unsigned": false,
-          "autoincrement": false,
-          "primary": false,
-          "nullable": false,
-          "mappedType": "text"
-        },
-        "name": {
-          "name": "name",
-          "type": "text",
-          "unsigned": false,
-          "autoincrement": false,
-          "primary": false,
-          "nullable": false,
-          "mappedType": "text"
-        }
-      },
-      "name": "currency",
-      "schema": "public",
-      "indexes": [
-        {
-          "keyName": "currency_pkey",
-          "columnNames": [
-            "code"
-          ],
-          "composite": false,
-          "primary": true,
-          "unique": true
-        }
-      ],
-      "checks": [],
-      "foreignKeys": {}
-    },
     {
       "columns": {
         "id": {
@@ -172,19 +117,6 @@
       ],
       "checks": [],
       "foreignKeys": {
-        "money_amount_currency_code_foreign": {
-          "constraintName": "money_amount_currency_code_foreign",
-          "columnNames": [
-            "currency_code"
-          ],
-          "localTableName": "public.money_amount",
-          "referencedColumnNames": [
-            "code"
-          ],
-          "referencedTableName": "public.currency",
-          "deleteRule": "set null",
-          "updateRule": "cascade"
-        }
       }
     },
     {

packages/pricing/src/migrations/Migration20230929122253.ts

@@ -2,10 +2,6 @@ import { Migration } from "@mikro-orm/migrations"
 
 export class Migration20230929122253 extends Migration {
   async up(): Promise<void> {
-    this.addSql(
-      'create table if not exists "currency" ("code" text not null, "symbol" text not null, "symbol_native" text not null, "name" text not null, constraint "currency_pkey" primary key ("code"));'
-    )
-
     this.addSql(
       'create table if not exists "money_amount" ("id" text not null, "currency_code" text null, "amount" numeric null, "min_quantity" numeric null, "max_quantity" numeric null, constraint "money_amount_pkey" primary key ("id"));'
     )
@@ -67,10 +63,6 @@ export class Migration20230929122253 extends Migration {
       'create index "IDX_price_rule_price_set_money_amount_id" on "price_rule" ("price_set_money_amount_id");'
     )
 
-    this.addSql(
-      'alter table "money_amount" add constraint "money_amount_currency_code_foreign" foreign key ("currency_code") references "currency" ("code") on update cascade on delete set null;'
-    )
-
     this.addSql(
       'alter table "price_set_money_amount" add constraint "price_set_money_amount_price_set_id_foreign" foreign key ("price_set_id") references "price_set" ("id") on update cascade on delete cascade;'
     )