ChainSpec extensions (#3692)

* Add some chainspec tests and make sure we validate it.

* Manual implementation of Extension + Forks definitions.

* Move chain spec to separate crate.

* Allow using ChainSpec with extensions.

* Renames.

* Implement Extension derive.

* Implement Extension for Forks.

* Support specifying fork blocks.

* make for_blocks work

* Support forks correctly.

* Add a bunch of docs.

* Make fork blocks optional.

* Add missing docs.

* Fix build.

* Use struct for check_block params.

* Fix tests?

* Clean up.

substrate/core/telemetry/src/lib.rs

@@ -92,7 +92,7 @@ pub struct TelemetryConfig {
 /// maximum verbosity level.
 ///
 /// The URL string can be either a URL or a multiaddress.
-#[derive(Debug, Clone, Serialize, Deserialize)]
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
 pub struct TelemetryEndpoints(Vec<(String, u8)>);
 
 impl TelemetryEndpoints {