Add ChainstateManagerOpts, using as ::Options

[META] Although it seems like we don't need it for just one option,
       we're going to introduce another member to this struct *in the
       next commit*. In future patchsets for libbitcoinkernel decoupling
       it from ArgsManager, even more members will be added here.

src/test/util/setup_common.cpp

@@ -164,7 +164,10 @@ ChainTestingSetup::ChainTestingSetup(const std::string& chainName, const std::ve
 
     m_cache_sizes = CalculateCacheSizes(m_args);
 
-    m_node.chainman = std::make_unique<ChainstateManager>(chainparams);
+    const ChainstateManager::Options chainman_opts{
+        chainparams,
+    };
+    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);
 
     // Start script-checking threads. Set g_parallel_script_checks to true so they are used.