network: Add initial files and enet dependency

src/network/CMakeLists.txt

@@ -0,0 +1,16 @@
+add_library(network STATIC
+    network.cpp
+    network.h
+    packet.cpp
+    packet.h
+    room.cpp
+    room.h
+    room_member.cpp
+    room_member.h
+    verify_user.cpp
+    verify_user.h
+)
+
+create_target_directory_groups(network)
+
+target_link_libraries(network PRIVATE common enet Boost::boost)