feat: non-latin keyboard layout compatible shortcuts

[seorgiy]

Problem

The keyboard shortcuts requires using a Latin-based keyboard layout.
For example, Ctrl+k on the Russian layout would result in Ctrl+л.

Assumptions

• We want to stay with github/hotkeys library
• We don't want to use event.code instead of event.key, as it discussed here
• We don't want to mess with the KeyboardEvent due to possible browser-specific troubles and the security reasons
• Hotkeys should work simultaneously in a Latin and non-Latin variant

Solution

Duplicate all the hotkeys for language-specific variants based on provided language key maps such as { k: 'л' } for the Russian example. This PR contains the Russian hotkey map and the functionality to add more.

Concerns

• Still not sure we shouldn't switch for event.code approach
• If we add a lot of key maps, it may lead to some conflicts, so we probably should make them user-controllable like an option «add keyboard support for: [multiple select from allowed keyboards]». But it doesn't make sense until we agree on the approach
• In general this PR conflicts with custom shortcuts but it's mergeable