[ServerProject] Concurrency problem when too many bots

[Akwd22]

The game bug when there is more than ~3 bots because they connect to the server at the very same time.

The bug is located between the thread which listens to the connections and the thread which connects the bots.

• Temporary fix: put a sleep before connecting each bot.
• Permanent fix: delay the connection of a new bot until listenConnection() has said to continue (block after accept(), unblock before accept()).