Dynamic Benchmarking DB Whitelist (#6815)

* Add `get_whitelist` api

* add whitelisted caller

* Whitelist caller

* remove caller 0

* initial piping of origin (not actual value yet)

* remove attempt to pass origin around

* Add whitelist for `DidUpdate` storage on `pallet_timestamp`

* fix traits

* only add to whitelist if !contains

* PassBy not implemented error

* Whitelist read/writes explicitly per key

* update docs

* reduce trait constraint

* copy pasta

* Apply suggestions from code review

Co-authored-by: Guillaume Thiolliere <gui.thiolliere@gmail.com>
Co-authored-by: Alexander Popiak <alexander.popiak@parity.io>

* rename functions @apopiak

* missed some renaming

* enable doc tests

* Update docs

Co-authored-by: Guillaume Thiolliere <gui.thiolliere@gmail.com>
Co-authored-by: Alexander Popiak <alexander.popiak@parity.io>

substrate/primitives/runtime-interface/src/impls.rs

@@ -537,3 +537,7 @@ impl PassBy for sp_wasm_interface::ValueType {
 impl PassBy for sp_wasm_interface::Value {
 	type PassBy = Codec<sp_wasm_interface::Value>;
 }
+
+impl PassBy for sp_storage::TrackedStorageKey {
+	type PassBy = Codec<Self>;
+}