Rework storage iterators (#13284)

* Rework storage iterators

* Make sure storage iteration is also accounted for when benchmarking

* Use `trie-db` from crates.io

* Appease clippy

* Bump `trie-bench` to 0.35.0

* Fix tests' compilation

* Update comment to clarify how `IterArgs::start_at` works

* Add extra tests

* Fix iterators on `Client` so that they behave as before

* Add extra `unwrap`s in tests

* More clippy fixes

* Come on clippy, give me a break already

* Rename `allow_missing` to `stop_on_incomplete_database`

* Add `#[inline]` to `with_recorder_and_cache`

* Use `with_recorder_and_cache` in `with_trie_db`; add doc comment

* Simplify code: use `with_trie_db` in `next_storage_key_from_root`

* Remove `expect`s in the benchmarking CLI

* Add extra doc comments

* Move `RawIter` before `TrieBackendEssence` (no code changes; just cut-paste)

* Remove a TODO in tests

* Update comment for `StorageIterator::was_complete`

* Update `trie-db` to 0.25.1

substrate/primitives/trie/src/lib.rs

@@ -51,7 +51,7 @@ pub use trie_db::{
 	nibble_ops,
 	node::{NodePlan, ValuePlan},
 	CError, DBValue, Query, Recorder, Trie, TrieCache, TrieConfiguration, TrieDBIterator,
-	TrieDBKeyIterator, TrieLayout, TrieMut, TrieRecorder,
+	TrieDBKeyIterator, TrieDBRawIterator, TrieLayout, TrieMut, TrieRecorder,
 };
 /// The Substrate format implementation of `TrieStream`.
 pub use trie_stream::TrieStream;
@@ -442,6 +442,7 @@ fn keyspace_as_prefix_alloc(ks: &[u8], prefix: Prefix) -> (Vec<u8>, Option<u8>)
 
 impl<'a, DB: ?Sized, H> KeySpacedDB<'a, DB, H> {
 	/// instantiate new keyspaced db
+	#[inline]
 	pub fn new(db: &'a DB, ks: &'a [u8]) -> Self {
 		KeySpacedDB(db, ks, PhantomData)
 	}