[tintinhamans]

Merge after #664.

/net shows the settings for the next lobby mesh and the current route and ping to each player. /net relay force|auto requires relay connections or follows the service policy, and /net engine native|webrtc|auto selects a connection engine or follows the service choice. Without a value they show the setting and usage. Both apply when the next lobby mesh is created, existing connections are unchanged. /net reset clears both overrides. /forcerelay and /allowrelay stay as aliases for /net relay force and /net relay auto. The command works in the lobby and the game setup chat.

Forced relay keeps its own lobby group by xoring the real executable CRC with a constant, instead of the old fixed 123456. Repeating force does not replace the saved CRC, and auto and reset restore it only when relay was forced. The engine setting never changes the CRC.

It reads connection.relay_only and connection.ice_engine from the service config for the status lines and in the NetworkMesh constructor, where the override wins. The overrides replace the g_bForceRelay global.

Tested: builds x86 Release z_generals.