add NodeFeatures field to HostConfiguration and runtime API (#2177)

Adds a `NodeFeatures` bitfield value to the runtime `HostConfiguration`,
with the purpose of coordinating the enabling of node-side features,
such as: https://github.com/paritytech/polkadot-sdk/issues/628 and
https://github.com/paritytech/polkadot-sdk/issues/598.
These are features that require all validators enable them at the same
time, assuming all/most nodes have upgraded their node versions.

This PR doesn't add any feature yet. These are coming in future PRs.

Also adds a runtime API for querying the state of the client features
and an extrinsic for setting/unsetting a feature by its index in the bitfield.

Note: originally part of:
https://github.com/paritytech/polkadot-sdk/pull/1644, but posted as
standalone to be reused by other PRs until the initial PR is merged

cumulus/parachains/integration-tests/emulated/chains/relays/rococo/src/lib.rs

@@ -24,7 +24,7 @@ use emulated_integration_tests_common::{
 
 // Rococo declaration
 decl_test_relay_chains! {
-	#[api_version(8)]
+	#[api_version(9)]
 	pub struct Rococo {
 		genesis = genesis::genesis(),
 		on_init = (),

cumulus/parachains/integration-tests/emulated/chains/relays/westend/src/lib.rs

@@ -24,7 +24,7 @@ use emulated_integration_tests_common::{
 
 // Westend declaration
 decl_test_relay_chains! {
-	#[api_version(8)]
+	#[api_version(9)]
 	pub struct Westend {
 		genesis = genesis::genesis(),
 		on_init = (),