Adding benchmarking for new frame_election_provider_support (#11149)

* First stab at adding benchmarking for
`election-provider-support` onchain

* Adding `BoundedPhragMMS` and fixing stuff

* Fixing node runtime

* Fixing tests

* Finalising all benchmarking stuff

* better comments

* Better benchmarking config

* Better `WeightInfo` and benchmarking

* Fixing tests

* Adding some documentation

* Fixing some typos

* Incorporating review feedback

* cleanup of rustdocs

* rustdoc changes

* changes after code review

* Fixing some errors.

* Fixing dependencies post merge

* Bringing back `UnboundedExecution`

* Better rustdoc and naming

* Cargo.toml formatting

substrate/Cargo.lock

@@ -4998,6 +4998,7 @@ dependencies = [
  "pallet-conviction-voting",
  "pallet-democracy",
  "pallet-election-provider-multi-phase",
+ "pallet-election-provider-support-benchmarking",
  "pallet-elections-phragmen",
  "pallet-gilt",
  "pallet-grandpa",
@@ -5851,6 +5852,7 @@ dependencies = [
  "frame-system",
  "log 0.4.14",
  "pallet-balances",
+ "pallet-election-provider-support-benchmarking",
  "parity-scale-codec",
  "parking_lot 0.12.0",
  "rand 0.7.3",
@@ -5866,6 +5868,18 @@ dependencies = [
  "strum",
 ]
 
+[[package]]
+name = "pallet-election-provider-support-benchmarking"
+version = "4.0.0-dev"
+dependencies = [
+ "frame-benchmarking",
+ "frame-election-provider-support",
+ "frame-system",
+ "parity-scale-codec",
+ "sp-npos-elections",
+ "sp-runtime",
+]
+
 [[package]]
 name = "pallet-elections-phragmen"
 version = "5.0.0-dev"