[Floonet] add feature for height locked kernels (#2168)

* add feature for height locked kernels

* add function to compute kernel features appropriate for lock height, and use it

* only sign kernel-features relevant fields; refactor Features

* simplify invalid kernel logic

* remove unused height arg to reward::output and run some rustfmt

* replace nested if/else by match

api/src/handlers/utils.rs

@@ -44,8 +44,8 @@ pub fn get_output(
 	// For now we can just try both (but this probably needs to be part of the api
 	// params)
 	let outputs = [
-		OutputIdentifier::new(OutputFeatures::DEFAULT_OUTPUT, &commit),
-		OutputIdentifier::new(OutputFeatures::COINBASE_OUTPUT, &commit),
+		OutputIdentifier::new(OutputFeatures::PLAIN, &commit),
+		OutputIdentifier::new(OutputFeatures::COINBASE, &commit),
 	];
 
 	for x in outputs.iter() {

api/src/types.rs

@@ -251,10 +251,7 @@ impl OutputPrintable {
 		block_header: Option<&core::BlockHeader>,
 		include_proof: bool,
 	) -> OutputPrintable {
-		let output_type = if output
-			.features
-			.contains(core::transaction::OutputFeatures::COINBASE_OUTPUT)
-		{
+		let output_type = if output.is_coinbase() {
 			OutputType::Coinbase
 		} else {
 			OutputType::Transaction
@@ -278,11 +275,7 @@ impl OutputPrintable {
 		// We require the rewind() to be stable even after the PMMR is pruned and
 		// compacted so we can still recreate the necessary proof.
 		let mut merkle_proof = None;
-		if output
-			.features
-			.contains(core::transaction::OutputFeatures::COINBASE_OUTPUT)
-			&& !spent && block_header.is_some()
-		{
+		if output.is_coinbase() && !spent && block_header.is_some() {
 			merkle_proof = chain.get_merkle_proof(&out_id, &block_header.unwrap()).ok()
 		};