Add ChainstateManager::m_adjusted_time_callback

This decouples validation.cpp from netaddress.cpp (transitively,
timedata.cpp, and asmap.cpp).

This is important for libbitcoinkernel as:

- There is no reason for the consensus engine to be coupled with
  netaddress, timedata, and asmap
- Users of libbitcoinkernel can now easily supply their own
  std::function that provides the adjusted time.

See the src/Makefile.am changes for some satisfying removals.

src/test/util/setup_common.cpp

@@ -29,6 +29,7 @@
 #include <shutdown.h>
 #include <streams.h>
 #include <test/util/net.h>
+#include <timedata.h>
 #include <txdb.h>
 #include <util/strencodings.h>
 #include <util/string.h>
@@ -166,6 +167,7 @@ ChainTestingSetup::ChainTestingSetup(const std::string& chainName, const std::ve
 
     const ChainstateManager::Options chainman_opts{
         chainparams,
+        GetAdjustedTime,
     };
     m_node.chainman = std::make_unique<ChainstateManager>(chainman_opts);
     m_node.chainman->m_blockman.m_block_tree_db = std::make_unique<CBlockTreeDB>(m_cache_sizes.block_tree_db, true);