Add death screen to stock renderer

[loothero]

To enable players to easily distinguish between games that alive, it would be nice for the Renderer to feature a deathscreen for dead adventurers.

I think our current deathscreen could be a good template for this. Key parts of this screen are:

1. Logic in the renderer to look at health and if it's zero, call load_death_screen()
2. Show final xp/level, tombstone, with obituary below or on the tombstone.
3. Tombstone is onchain so renderer can access this directly but it's stored as a ByteArray so we may need to truncate it

Death screen should feature the LS skull logo in the top left which shows crown or gold|silver|bronze for top scores.