Add block construction prometheus metrics (#6030)

* Add basic authorship metrics

* fixes

* no arc

* move to crate

* Update client/proposer-metrics/Cargo.toml

Co-authored-by: Max Inden <mail@max-inden.de>

* remove prefix

* use HistogramTimer

* Update client/proposer-metrics/src/lib.rs

Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>

* Update client/basic-authorship/src/basic_authorship.rs

Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>

* Update client/basic-authorship/src/basic_authorship.rs

Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>

* Update client/basic-authorship/src/basic_authorship.rs

Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>

* Update client/basic-authorship/src/basic_authorship.rs

Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>

* Update client/basic-authorship/src/basic_authorship.rs

Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>

* Update client/proposer-metrics/src/lib.rs

Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>

* Update client/proposer-metrics/src/lib.rs

Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>

Co-authored-by: Max Inden <mail@max-inden.de>
Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>

substrate/Cargo.lock

@@ -5885,6 +5885,7 @@ dependencies = [
  "parking_lot 0.10.2",
  "sc-block-builder",
  "sc-client-api",
+ "sc-proposer-metrics",
  "sc-telemetry",
  "sc-transaction-pool",
  "sp-api",
@@ -5894,6 +5895,7 @@ dependencies = [
  "sp-inherents",
  "sp-runtime",
  "sp-transaction-pool",
+ "substrate-prometheus-endpoint",
  "substrate-test-runtime-client",
  "tokio-executor 0.2.0-alpha.6",
 ]
@@ -6601,6 +6603,14 @@ dependencies = [
  "wasm-timer",
 ]
 
+[[package]]
+name = "sc-proposer-metrics"
+version = "0.8.0-dev"
+dependencies = [
+ "log",
+ "substrate-prometheus-endpoint",
+]
+
 [[package]]
 name = "sc-rpc"
 version = "2.0.0-dev"