Allow passing UID to importer

This helps, for importers spitting out new resources to the res://
filesystem to actually hash them to generate deterministic UIDs.

This PR also fixes the determinism for translations.

tests/core/string/test_translation.h

@@ -161,7 +161,7 @@ TEST_CASE("[TranslationCSV] CSV import") {
 
 	List<String> gen_files;
 
-	Error result = import_csv_translation->import(TestUtils::get_data_path("translations.csv"),
+	Error result = import_csv_translation->import(0, TestUtils::get_data_path("translations.csv"),
 			"", options, nullptr, &gen_files);
 	CHECK(result == OK);
 	CHECK(gen_files.size() == 4);