Removal of "rust-extra" string translation

If it isn't used anywhere, we shouldn't ask for its translation

Signed-off-by: Aleksandrs Ļedovskis <aleksandrs@ledovskis.lv>
Add ru-RU localization

Signed-off-by: Aleksandrs Ļedovskis <aleksandrs@ledovskis.lv>
Merge pull request #98 from aledovsky/feature/rust-extra_l10n_removal

Removal of "rust-extra" string translation
Merge pull request #99 from aledovsky/feature/ru-RU_translation

Add ru-RU localization