Uniformize folder structure (#693)

* Uniformize folder structure

* Fix icons

* Fix icons

* Fix tests

* Fix tests

front/src/utils/isNonEmptyString.ts

@@ -0,0 +1,15 @@
+import { isDefined } from './isDefined';
+
+export function isNonEmptyString(
+  probableNonEmptyString: string | undefined | null,
+): probableNonEmptyString is string {
+  if (
+    isDefined(probableNonEmptyString) &&
+    typeof probableNonEmptyString === 'string' &&
+    probableNonEmptyString !== ''
+  ) {
+    return true;
+  }
+
+  return false;
+}