Autotests: EXERCISES WORDS RU page

Check web elements, excluding header and footer, on the 'Exercises "Words"' web page on the 'ru' local.
The page index in the [Site Structure](https://github.com/Brain-up/auto-tests-python/wiki/Site-Structure): C.14.06
The page url: https://brainup.site/groups/2/series/1