refactor, validation: Add ChainstateManagerOpts db options

Use ChainstateManagerOpts struct to remove ArgsManager uses from validation.cpp.

This commit does not change behavior.

src/test/util/setup_common.cpp

@@ -180,6 +180,7 @@ ChainTestingSetup::ChainTestingSetup(const std::string& chainName, const std::ve
 
     const ChainstateManager::Options chainman_opts{
         .chainparams = chainparams,
+        .datadir = m_args.GetDataDirNet(),
         .adjusted_time_callback = GetAdjustedTime,
         .check_block_index = true,
     };