chore: Move buying controller to utils

erpnext/regional/italy/sales_invoice.js

@@ -1,25 +0,0 @@
-erpnext.setup_e_invoice_button = (doctype) => {
-	frappe.ui.form.on(doctype, {
-		refresh: (frm) => {
-			if(frm.doc.docstatus == 1) {
-				frm.add_custom_button('Generate E-Invoice', () => {
-					frm.call({
-						method: "erpnext.regional.italy.utils.generate_single_invoice",
-						args: {
-							docname: frm.doc.name
-						},
-						callback: function(r) {
-							frm.reload_doc();
-							if(r.message) {
-								open_url_post(frappe.request.url, {
-									cmd: 'frappe.core.doctype.file.file.download_file',
-									file_url: r.message
-								});
-							}
-						}
-					});
-				});
-			}
-		}
-	});
-};