Localize Launcher and Wizard

See #6411 (closed)

Summary of changes:

1. Split files/ui to application-specific directories to localize them.
2. Add .ts translation files to Git.
3. Add a make translations target to update that files by strings from source code.
4. Add a Russian translation for Launcher and Wizard (but not for OpenMW-CS, because it was not written with localization in mind).
5. Build .qm localization files when developer builds a project and put them to resources folder.
6. Automatically select language for Launcher and Wizard depending on system locale for Wizard (we already do it for Launcher).
7. Add a CI job to check if an MR developer did not forget to update translation files.

Checked on Windows and Linux.

Note that maybe it makes no sense to add English translation files - the text will be the same as in source code.