Fixed bug, incorrect auto-generation Category URL for some groups of symbols (idish, cirrilic, é, ä, and other).

Solution:
URL formatting for Product works fine. Using Product's function formatUrlKey as basement for correct Category formatting.

Samples:
product : `абвгдеёжъ` -> `abvgdejozh`
category: `абвгдеёжъ` -> `d-d-d-d-d-d-n-d-ns`

What was done:
* Fixed bug.
* Created Helper for formating string to URL (Magento\Url\Helper\Format).
* Changed function formatUrlKey in Product and Category Model to new Helper using.
* Added function formatUrlKey for auto generation URL in Magento\Cms-Page.