Add map flares for observers

[Langbart]

A suggestion was made to allow the Map Flare feature for observers: ​Keep torch function on minimap after game has ended (18/Aug/21)

[Feldfeld]

As I said in the thread, for me the ideal would be that observers can flare to other observers at any time. On top of that, these additionnal features would be nice:

• If a player is eliminated/has won he is considered an observer
• At least for observers, and it could potentially be an option for player as well: have a small notification in the chat, something like "Feldfeld has flared the map!". That way, even without colors observers have a good idea who actually flared the map.
• Eliminated players could keep their color when flaring to other observers.

[Stan]

Unlikely to get done for A26

[Freagarach]

Pushing back.