Add method to get bound local address to ENetConnection

[Kaleb-Reid]

There was already a method to get the port but I could not find a way to get the address. I noticed that the wildcard addresses have weird behaviour, not sure if I need to document that or where I would.

According to ss on Linux, when using the built-in ENet using * or :: as the bind address will actually bind to * and be accessible over IPv4 and 6, but using enet_socket_get_address will return ::. When using 0.0.0.0 as the bind address, enet_socket_get_address will return 0.0.0.0 but the socket will be bound to ::ffff:0.0.0.0 and will be accessible over IPv4 normally, but can only be accessed by IPv6 using an IPv4-mapped IPv6 address (e.g. ::ffff:7f00:1 / ::ffff:127.0.0.1).

When not using the built-in ENet, * and 0.0.0.0 will bind to 0.0.0.0 and enet_socket_get_address will return 0.0.0.0.

Given that setting :: and * both result in * being bound I chose to always return *. I also chose to leave 0.0.0.0 because its functionality is actually different from * and ::.

[AThousandShips]

Suggested change

	ERR_FAIL_COND_V_MSG(enet_socket_get_address(host->socket, &address), IPAddress(), "Unable to get socket address");
	ERR_FAIL_COND_V_MSG(enet_socket_get_address(host->socket, &address), IPAddress(), "Unable to get socket address.");