Merge bitcoin/bitcoin#22951: consensus: move amount.h into consensus

9d0379cea6 consensus: use <cstdint> over <stdint.h> in amount.h (fanquake)
863e52fe63 consensus: make COIN & MAX_MONEY constexpr (fanquake)
d09071da5b [MOVEONLY] consensus: move amount.h into consensus (fanquake)

Pull request description:

  A first step (of a few) towards some source code reorganization, as well as making libbitcoinconsensus slightly more self contained.

  Related to #15732.

ACKs for top commit:
  MarcoFalke:
    concept ACK 9d0379cea6 🏝

Tree-SHA512: 97fc79262dcb8c00996852a288fee69ddf8398ae2c95700bba5b326f1f38ffcfaf8fa66e29d0cb446d9b3f4e608a96525fae0c2ad9cd531ad98ad2a4a687cd6a

src/node/coinstats.h

@@ -6,9 +6,9 @@
 #ifndef BITCOIN_NODE_COINSTATS_H
 #define BITCOIN_NODE_COINSTATS_H
 
-#include <amount.h>
 #include <chain.h>
 #include <coins.h>
+#include <consensus/amount.h>
 #include <streams.h>
 #include <uint256.h>
 

src/node/psbt.cpp

@@ -2,8 +2,8 @@
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
-#include <amount.h>
 #include <coins.h>
+#include <consensus/amount.h>
 #include <consensus/tx_verify.h>
 #include <node/psbt.h>
 #include <policy/policy.h>