Save/Load game should preserve group shortcuts

[DmytroSokhach]

Description

Assume group shortcuts are not preserved while saving the game, or not applied while loading game

Expected Behaviour

Group shortcuts would remain the same as they were while clicking Save button.

Actual Behaviour

Game loads from save point, but shortcuts are empty and need to re-select and re-assign groups from scratch.

Reproduction steps

1. Start offline game

2. Assign couple groups to certain units

3. Click Save game button on top right

4. Exit to Lobby

5. Load game

Other

No response