refactor, validation: Add ChainstateManagerOpts db options

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

This commit does not change behavior.

src/test/validation_chainstatemanager_tests.cpp

@@ -374,6 +374,7 @@ struct SnapshotTestSetup : TestChain100Setup {
             BOOST_CHECK_EQUAL(chainman.GetAll().size(), 0);
             const ChainstateManager::Options chainman_opts{
                 .chainparams = ::Params(),
+                .datadir = m_args.GetDataDirNet(),
                 .adjusted_time_callback = GetAdjustedTime,
             };
             // For robustness, ensure the old manager is destroyed before creating a