game: Split function to initialize player off from players_init()
player: Assign proper names to some fields
Allow players to be added dynamically to the game

game: Add function game_add_player() to initialize new player.
Store player face in player object and load from save games.
Recalculate map values dependent on player count when a new player is added.
game: Initialize player directly without using player_init_t struct

Remove player_init_t structs from game.
game: Move memory allocation to game_init() and game_init_map()