Drop unused init.h includes

These were entirely unused, as based on successful compilation
and a grep for:
  \bStartShutdown\(\)|\bShutdownRequested\(\)|\bInterrupt\(\)|\bShutdown\(\)|\bInitLogging\(\)|\bInitParameterInteraction\(\)|\bAppInitBasicSetup\(\)|\bAppInitParameterInteraction\(\)|\bAppInitSanityChecks\(\)|\bAppInitLockDataDirectory\(\)|\bAppInitMain\(\)|\bSetupServerArgs\(\)|\bLicenseInfo\(\)|g_wallet_init_interface|init.h

src/net_processing.cpp

@@ -11,7 +11,6 @@
 #include <chainparams.h>
 #include <consensus/validation.h>
 #include <hash.h>
-#include <init.h>
 #include <validation.h>
 #include <merkleblock.h>
 #include <netmessagemaker.h>

src/qt/bitcoin.cpp

@@ -26,7 +26,6 @@
 #include <qt/walletmodel.h>
 #endif
 
-#include <init.h>
 #include <interfaces/handler.h>
 #include <interfaces/node.h>
 #include <rpc/server.h>

src/qt/bitcoingui.cpp

@@ -29,7 +29,6 @@
 #endif
 
 #include <chainparams.h>
-#include <init.h>
 #include <interfaces/handler.h>
 #include <interfaces/node.h>
 #include <ui_interface.h>

src/qt/signverifymessagedialog.cpp

@@ -10,7 +10,6 @@
 #include <qt/platformstyle.h>
 #include <qt/walletmodel.h>
 
-#include <init.h>
 #include <key_io.h>
 #include <validation.h> // For strMessageMagic
 #include <wallet/wallet.h>

src/qt/splashscreen.cpp

@@ -11,7 +11,6 @@
 #include <qt/networkstyle.h>
 
 #include <clientversion.h>
-#include <init.h>
 #include <interfaces/handler.h>
 #include <interfaces/node.h>
 #include <interfaces/wallet.h>

src/rpc/misc.cpp

@@ -7,7 +7,6 @@
 #include <clientversion.h>
 #include <core_io.h>
 #include <crypto/ripemd160.h>
-#include <init.h>
 #include <key_io.h>
 #include <validation.h>
 #include <httpserver.h>

src/rpc/rawtransaction.cpp

@@ -8,7 +8,6 @@
 #include <consensus/validation.h>
 #include <core_io.h>
 #include <index/txindex.h>
-#include <init.h>
 #include <keystore.h>
 #include <validation.h>
 #include <validationinterface.h>

src/validationinterface.cpp

@@ -5,7 +5,6 @@
 
 #include <validationinterface.h>
 
-#include <init.h>
 #include <primitives/block.h>
 #include <scheduler.h>
 #include <sync.h>