Finish documenting #[pallet::xxx] macros (#2638)

Closes https://github.com/paritytech/polkadot-sdk-docs/issues/35

- Moves pallet proc macro docs to `frame_support`
- Adds missing docs
- Revise revise existing docs, adding compiling doctests where
appropriate

---------

Co-authored-by: command-bot <>
Co-authored-by: Kian Paimani <5588131+kianenigma@users.noreply.github.com>

Cargo.lock

@@ -5750,6 +5750,7 @@ dependencies = [
  "sp-staking",
  "sp-state-machine",
  "sp-std 14.0.0",
+ "sp-timestamp",
  "sp-tracing 16.0.0",
  "sp-weights",
  "static_assertions",