LAN Announcer

Update the jar icon.

Added a check in onInitialize that ensures we run iff FabricLoader.getInstance().getEnvironmentType() == net.fabricmc.api.EnvType.SERVER.

It ensures that if we are installed on a client, we do nothing.

If we are installed/running on a client, we emit one warning and that's it.

First release - Added support for sending multicast pings over UDP.