feat(medusa): Align product import and export (#2471)

**What**

Create a data structure that facilitate the addition of new column descriptor for both export and import and ensure that the column name is shared between bother import and export to facilitate the import with an exported file. 

**Tests**

Add an additional integration tests that export a file, update the data, and re import the same file

FIXES CORE-716
FIXES CORE-713

packages/medusa/src/interfaces/csv-parser.ts

@@ -40,21 +40,30 @@ export abstract class AbstractCsvValidator<TCsvLine, TBuiltLine>
   ): Promise<boolean | never>
 }
 
-export type CsvSchemaColumn<TCsvLine, TBuiltLine> = {
-  name: string
+export type CsvSchemaColumn<
+  TCsvLine,
+  TBuiltLine,
+  NameAsOptional = false
+> = (NameAsOptional extends false
+  ? {
+      name: string
+    }
+  : {
+      name?: string
+    }) & {
   required?: boolean
   validator?: AbstractCsvValidator<TCsvLine, TBuiltLine>
 } & (
-  | {
-      mapTo?: string
-      transform?: ColumnTransformer<TCsvLine>
-    }
-  | {
-      match?: RegExp
-      reducer?: ColumnReducer<TCsvLine, TBuiltLine>
-      transform?: ColumnTransformer<TCsvLine>
-    }
-)
+    | {
+        mapTo?: string
+        transform?: ColumnTransformer<TCsvLine>
+      }
+    | {
+        match?: RegExp
+        reducer?: ColumnReducer<TCsvLine, TBuiltLine>
+        transform?: ColumnTransformer<TCsvLine>
+      }
+  )
 
 export type ColumnTransformer<TCsvLine> = (
   value: string,