Expose MMR root through runtime API - use it in BEEFY client (#11183)

* beefy-gadget: allow custom runtime api provider

* beefy-gadget: use mock runtime api in tests

* pallet-mmr: expose mmr root from state through runtime API

* beefy-gadget: get mmr root from runtime state

* pallet-beefy-mmr: remove MmrRoot from header digests

* frame/mmr: move mmr primitives out of frame

* frame/mmr: completely move primitives out of frame

* address review comments

* beefy-mmr: bring back mmr root from header digest

* clippy fixes for rustc 1.60

* address review comments

substrate/Cargo.toml

@@ -101,7 +101,6 @@ members = [
 	"frame/lottery",
 	"frame/membership",
 	"frame/merkle-mountain-range",
-	"frame/merkle-mountain-range/primitives",
 	"frame/merkle-mountain-range/rpc",
 	"frame/multisig",
 	"frame/nicks",
@@ -172,6 +171,7 @@ members = [
 	"primitives/keyring",
 	"primitives/keystore",
 	"primitives/maybe-compressed-blob",
+	"primitives/merkle-mountain-range",
 	"primitives/npos-elections",
 	"primitives/npos-elections/fuzzer",
 	"primitives/offchain",