Merge #15163: Correct units for "-dbcache" and "-prune"

6f6514a080 Correct units for "-dbcache" and "-prune" (Hennadii Stepanov)

Pull request description:

  Actually, all `dbcache`-related values in the code are measured in MiB (not in megabytes, MB) or in bytes (e.g., `nTotalCache`).

  See: https://github.com/bitcoin/bitcoin/blob/master/src/txdb.h

  ba8c8b2227/src/init.cpp (L1405-L1424)

  Also, "-prune" is fixed:
  1. The GUI values in GB are translated to the node values in MiB correctly.
  2. The maximum of the "prune" `QSpinBox` is not limited by default value of 99 (GB).

  Fix: #15106

Tree-SHA512: 151ec43b31b1074db8b345fedb1dcc10bde225899a5296bfc183f57e1553d13ac27db8db100226646769ad03c9fcab29d88763065a471757c6c41ac51108459d

src/qt/intro.cpp

@@ -10,6 +10,7 @@
 #include <qt/intro.h>
 #include <qt/forms/ui_intro.h>
 
+#include <qt/guiconstants.h>
 #include <qt/guiutil.h>
 
 #include <interfaces/node.h>
@@ -21,7 +22,6 @@
 
 #include <cmath>
 
-static const uint64_t GB_BYTES = 1000000000LL;
 /* Total required space (in GB) depending on user choice (prune, not prune) */
 static uint64_t requiredSpace;