Kernel: Remove the NE2000 PCI network adapter driver

Nobody tests this network card as the person who added it, Jean-Baptiste
Boric (known as boricj) is not an active contributor in the project now.
After a discussion with him on the Discord server, we agreed it's for
the best to remove the driver, as for two reasons:
- The original author (boricj) agreed to do this, stating that he will
  not be able to test the driver anymore after his Athlon XP machine is
  no longer supported after the removal of the i686 port.
- It was agreed that the NE2000 network card family is far from the
  ideal hardware we would want to support, similarly to the RTL8139 that
  got removed recently for almost the same reason.

Kernel/Net/NetworkingManagement.cpp

@@ -13,7 +13,6 @@
 #include <Kernel/Net/Intel/E1000ENetworkAdapter.h>
 #include <Kernel/Net/Intel/E1000NetworkAdapter.h>
 #include <Kernel/Net/LoopbackAdapter.h>
-#include <Kernel/Net/NE2000/NetworkAdapter.h>
 #include <Kernel/Net/NetworkingManagement.h>
 #include <Kernel/Net/Realtek/RTL8168NetworkAdapter.h>
 #include <Kernel/Sections.h>
@@ -99,7 +98,6 @@ struct PCINetworkDriverInitializer {
 
 static constexpr PCINetworkDriverInitializer s_initializers[] = {
     { RTL8168NetworkAdapter::probe, RTL8168NetworkAdapter::create },
-    { NE2000NetworkAdapter::probe, NE2000NetworkAdapter::create },
     { E1000NetworkAdapter::probe, E1000NetworkAdapter::create },
     { E1000ENetworkAdapter::probe, E1000ENetworkAdapter::create },
 };