[ru] Localize `Stateful Apps` into Russian

[kirkonru]

Description

This Issue is to localize Stateful Apps into Russian.

Checklist before opening your PR (put x in the checkboxes) — note that you have to add this checklist to your PR and check all the boxes for it to be approved.

• [] :warning: This PR uses the dev-ru branch as a source/target.
• [] This PR does not contain plagiarism
  • don’t copy other people’s work unless you are quoting and contributing it to them.
• [] I have signed off on all commits
  • signing off (ex: git commit -s) is to affirm that commits comply DCO. If you are working locally, you could add an alias to your gitconfig by running git config --global alias.ci "commit -s".

ETA: TBD

Useful links: Как внести свой вклад Руководство по стилю

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[vickylikh]

I'd like to work on this issue.

[kirkonru]

You're assigned!