Docs for Frame Benchmarking (#7121)

* remove test benchmark pallet

* docs

* finish docs

* Update README.md

* simplify intro

* introduce weight later

* Apply suggestions from code review

Co-authored-by: David <dvdplm@gmail.com>
Co-authored-by: joe petrowski <25483142+joepetrowski@users.noreply.github.com>
Co-authored-by: Kian Paimani <5588131+kianenigma@users.noreply.github.com>

* Apply suggestions from code review

Co-authored-by: David <dvdplm@gmail.com>
Co-authored-by: joe petrowski <25483142+joepetrowski@users.noreply.github.com>

* Apply suggestions from code review

Co-authored-by: joe petrowski <25483142+joepetrowski@users.noreply.github.com>
Co-authored-by: David <dvdplm@gmail.com>

* Apply suggestions from code review

Co-authored-by: David <dvdplm@gmail.com>
Co-authored-by: joe petrowski <25483142+joepetrowski@users.noreply.github.com>

* Update frame/benchmarking/README.md

Co-authored-by: David <dvdplm@gmail.com>

* Update frame/benchmarking/README.md

* Update frame/benchmarking/README.md

Co-authored-by: joe petrowski <25483142+joepetrowski@users.noreply.github.com>

* Update README.md

* Update README.md

* Update README.md

* Update README.md

Co-authored-by: David <dvdplm@gmail.com>
Co-authored-by: joe petrowski <25483142+joepetrowski@users.noreply.github.com>
Co-authored-by: Kian Paimani <5588131+kianenigma@users.noreply.github.com>

substrate/Cargo.lock

@@ -4318,20 +4318,6 @@ dependencies = [
  "sp-std",
 ]
 
-[[package]]
-name = "pallet-benchmark"
-version = "2.0.0-rc6"
-dependencies = [
- "frame-benchmarking",
- "frame-support",
- "frame-system",
- "parity-scale-codec",
- "serde",
- "sp-io",
- "sp-runtime",
- "sp-std",
-]
-
 [[package]]
 name = "pallet-collective"
 version = "2.0.0-rc6"