Merge bitcoin/bitcoin#27636: kernel: Remove util/system from kernel library, interface_ui from validation.

7d3b35004b refactor: Move system from util to common library (TheCharlatan)
7eee356c0a refactor: Split util::AnyPtr into its own file (TheCharlatan)
44de325d95 refactor: Split util::insert into its own file (TheCharlatan)
9ec5da36b6 refactor: Move ScheduleBatchPriority to its own file (TheCharlatan)
f871c69191 kernel: Add warning method to notifications (TheCharlatan)
4452707ede kernel: Add progress method to notifications (TheCharlatan)
84d71457e7 kernel: Add headerTip method to notifications (TheCharlatan)
447761c822 kernel: Add notification interface (TheCharlatan)

Pull request description:

  This pull request is part of the `libbitcoinkernel` project https://github.com/bitcoin/bitcoin/issues/27587 https://github.com/bitcoin/bitcoin/projects/18 and more specifically its "Step 2: Decouple most non-consensus code from libbitcoinkernel".

  ---

  It removes the kernel library's dependency on `util/system` and `interface_ui`. `util/system` contains networking and shell-related code that should not be part of the kernel library. The following pull requests prepared `util/system` for this final step: https://github.com/bitcoin/bitcoin/pull/27419 https://github.com/bitcoin/bitcoin/pull/27254 https://github.com/bitcoin/bitcoin/pull/27238.

  `interface_ui` defines functions for a more general node interface and has a dependency on `boost/signals2`. After applying the patches from this pull request, the kernel's reliance on boost is down to `boost::multiindex`.

  The approach implemented here introduces some indirection, which makes the code a bit harder to read. Any suggestions for improving or reworking this pull request to make it more concise, or even reworking it into a more proper interface, are appreciated.

ACKs for top commit:
  MarcoFalke:
    re-ACK 7d3b35004b (no change) 🎋
  stickies-v:
    Code Review ACK 7d3b35004b
  hebasto:
    re-ACK 7d3b35004b, only last two commits dropped since my [recent](https://github.com/bitcoin/bitcoin/pull/27636#pullrequestreview-1435394620) review.

Tree-SHA512: c8cfc698dc9d78e20191c444708f2d957501229abe95e5806106d1126fb9c5fbcee686fb55645658c0107ce71f10646f37a2fdf7fde16bbf22cbf1ac885dd08d

src/qt/bitcoin.cpp

@@ -11,6 +11,7 @@
 #include <chainparams.h>
 #include <common/args.h>
 #include <common/init.h>
+#include <common/system.h>
 #include <init.h>
 #include <interfaces/handler.h>
 #include <interfaces/init.h>
@@ -32,7 +33,6 @@
 #include <uint256.h>
 #include <util/exception.h>
 #include <util/string.h>
-#include <util/system.h>
 #include <util/threadnames.h>
 #include <util/translation.h>
 #include <validation.h>

src/qt/bitcoingui.cpp

@@ -30,16 +30,17 @@
 #include <qt/macdockiconhandler.h>
 #endif
 
-#include <functional>
 #include <chain.h>
 #include <chainparams.h>
+#include <common/system.h>
 #include <interfaces/handler.h>
 #include <interfaces/node.h>
 #include <node/interface_ui.h>
-#include <util/system.h>
 #include <util/translation.h>
 #include <validation.h>
 
+#include <functional>
+
 #include <QAction>
 #include <QActionGroup>
 #include <QApplication>

src/qt/clientmodel.cpp

@@ -12,11 +12,11 @@
 
 #include <clientversion.h>
 #include <common/args.h>
+#include <common/system.h>
 #include <interfaces/handler.h>
 #include <interfaces/node.h>
 #include <net.h>
 #include <netbase.h>
-#include <util/system.h>
 #include <util/threadnames.h>
 #include <util/time.h>
 #include <validation.h>

src/qt/optionsdialog.cpp

@@ -15,11 +15,11 @@
 #include <qt/guiutil.h>
 #include <qt/optionsmodel.h>
 
+#include <common/system.h>
 #include <interfaces/node.h>
-#include <validation.h> // for DEFAULT_SCRIPTCHECK_THREADS and MAX_SCRIPTCHECK_THREADS
 #include <netbase.h>
-#include <txdb.h> // for -dbcache defaults
-#include <util/system.h>
+#include <txdb.h>
+#include <validation.h>
 
 #include <chrono>
 

src/qt/rpcconsole.cpp

@@ -10,6 +10,7 @@
 #include <qt/forms/ui_debugwindow.h>
 
 #include <chainparams.h>
+#include <common/system.h>
 #include <interfaces/node.h>
 #include <qt/bantablemodel.h>
 #include <qt/clientmodel.h>
@@ -21,7 +22,6 @@
 #include <rpc/server.h>
 #include <util/strencodings.h>
 #include <util/string.h>
-#include <util/system.h>
 #include <util/threadnames.h>
 
 #include <univalue.h>

src/qt/splashscreen.cpp

@@ -9,13 +9,13 @@
 #include <qt/splashscreen.h>
 
 #include <clientversion.h>
+#include <common/system.h>
 #include <interfaces/handler.h>
 #include <interfaces/node.h>
 #include <interfaces/wallet.h>
 #include <qt/guiutil.h>
 #include <qt/networkstyle.h>
 #include <qt/walletmodel.h>
-#include <util/system.h>
 #include <util/translation.h>
 
 #include <functional>

src/qt/test/rpcnestedtests.cpp

@@ -4,12 +4,12 @@
 
 #include <qt/test/rpcnestedtests.h>
 
+#include <common/system.h>
 #include <interfaces/node.h>
-#include <rpc/server.h>
 #include <qt/rpcconsole.h>
+#include <rpc/server.h>
 #include <test/util/setup_common.h>
 #include <univalue.h>
-#include <util/system.h>
 
 #include <QTest>
 

src/qt/transactiondesc.cpp

@@ -13,12 +13,12 @@
 #include <qt/paymentserver.h>
 #include <qt/transactionrecord.h>
 
+#include <common/system.h>
 #include <consensus/consensus.h>
 #include <interfaces/node.h>
 #include <interfaces/wallet.h>
 #include <key_io.h>
 #include <policy/policy.h>
-#include <util/system.h>
 #include <validation.h>
 #include <wallet/types.h>