Split non/kernel chainparams

Moves chainparams code not using the ArgsManager to the kernel.

Subsequently use the kernel chainparams header now where possible in
order to further decouple chainparams call sites from gArgs.

src/bitcoin-chainstate.cpp

@@ -11,6 +11,7 @@
 //
 // It is part of the libbitcoinkernel project.
 
+#include <kernel/chainparams.h>
 #include <kernel/checks.h>
 #include <kernel/context.h>
 #include <kernel/validation_cache_sizes.h>
@@ -52,7 +53,7 @@ int main(int argc, char* argv[])
 
     // SETUP: Misc Globals
     SelectParams(CBaseChainParams::MAIN);
-    const CChainParams& chainparams = Params();
+    auto chainparams = CChainParams::Main();
 
     kernel::Context kernel_context{};
     // We can't use a goto here, but we can use an assert since none of the
@@ -81,7 +82,7 @@ int main(int argc, char* argv[])
 
     // SETUP: Chainstate
     const ChainstateManager::Options chainman_opts{
-        .chainparams = chainparams,
+        .chainparams = *chainparams,
         .datadir = gArgs.GetDataDirNet(),
         .adjusted_time_callback = NodeClock::now,
     };