Merge: + client: add digit grouping for numbers on the dashboard

Closes #1423

Squashed commit of the following:

commit 6e5de427c48577ebbe4d963f817b66fed9b29bb4
Author: Ildar Kamalov <i.kamalov@adguard.com>
Date:   Wed Mar 11 17:56:39 2020 +0300

    + client: add digit grouping for numbers on the dashboard

client/src/helpers/helpers.js

@@ -449,3 +449,12 @@ export const getCurrentFilter = (url, filters) => {
 
     return { name: '', url: '' };
 };
+
+/**
+ * @param number Number to format
+ * @returns string Returns a string with a language-sensitive representation of this number
+ */
+export const formatNumber = (num) => {
+    const currentLanguage = i18n.languages[0] || DEFAULT_LANGUAGE;
+    return num.toLocaleString(currentLanguage);
+};