I've done it partially, but quckly.
1) I copied *us.js Script libraries into *ru.js
2) I translated some strings in language_ressources_ru.js, including these:
var onimod_dateformat='FR';// US or FR
var onimod_dateseparator='.';
var onimod_timeseparator=':';
3) Form: Preferances
Field: Lang
Formula: SupportedLanguageCodes := "ru" : "us";
3) Form: Preferances
Field: Language
Allowable Keywords:
English | us<br/>
Русский | ru<br/>
4) Form: Configuration_Profile
Field: DefaultLanguage
Allowable Keywords:
English | us<br/>
Русский | ru<br/>
5) It seems… I might forget something…