feat: Item validate cost, income and inventory account type.

feat: Style sales and purchases forms - 80% progress.
feat: Validate purchase-able and sell-able items in invoices and bills.
feat: Fix bugs in inventory FIFO/LIFO cost methods.

client/src/containers/Sales/Invoice/InvoiceFormHeader.js

@@ -68,8 +68,8 @@ function InvoiceFormHeader({
   );
 
   return (
-    <div className={'invoice-form'}>
-      <div className={'invoice__primary-section'}>
+    <div class="page-form page-form--invoice">
+      <div className={'page-form__primary-section'}>
         {/* customer name */}
         <FormGroup
           label={<T id={'customer_name'} />}