thread local chain type vs global chain type (#3327)

* Introduce GLOBAL_CHAIN_TYPE and make CHAIN_TYPE thread_local.
This makes testing more explicit and significantly more robust.

* set_local_chain_type() in tests

* cleanup - weird

* get pool tests working with explicit local chain_type config

* core tests working with explicit local chain_type

* p2p tests working with explicit local chain_type

* store tests working

* cleanup, feedback

etc/gen_gen/src/bin/gen_gen.rs

@@ -92,7 +92,7 @@ fn main() {
 
 	{
 		// setup a tmp chain to set block header roots
-		core::global::set_mining_mode(core::global::ChainTypes::UserTesting);
+		core::global::set_local_chain_type(core::global::ChainTypes::UserTesting);
 		let tmp_chain = setup_chain(".grin.tmp", core::pow::mine_genesis_block().unwrap());
 		tmp_chain.set_txhashset_roots(&mut gen).unwrap();
 	}
@@ -103,7 +103,7 @@ fn main() {
 	gen.header.prev_root = core::core::hash::Hash::from_hex(&h1).unwrap();
 
 	// mine a Cuckaroo29 block
-	core::global::set_mining_mode(core::global::ChainTypes::Mainnet);
+	core::global::set_local_chain_type(core::global::ChainTypes::Mainnet);
 	let plugin_lib = cuckoo::PluginLibrary::new(PLUGIN_PATH).unwrap();
 	let mut params = plugin_lib.get_default_params();
 	params.mutate_nonce = false;
@@ -216,7 +216,7 @@ fn update_genesis_rs(gen: &core::core::Block) {
 		"excess".to_string(),
 		format!(
 			"Commitment::from_vec(util::from_hex({:x?}.to_string()).unwrap())",
-			gen.kernels()[0].excess.to_hex())
+			gen.kernels()[0].excess.to_hex()
 		),
 	));
 	replacements.push((