Simplify BABE pre-digest definitions (#5289)

* Init vrf crate without type alias

* Generic PreDigest definition for BABE

* Fix BABE vrf interface change

* Missing default-features def in sp-consensus-babe

* Fix sp-consensus-babe compile

* frame-babe: fix type inference

* Unify type definitions of vrf output/proof and randomness

* frame-babe: fix tests

* Bump node impl version

* Update cargo lock

* Derive Copy for RawVRFOutput and RawVRFProof

* Fix duplicated derive

Co-authored-by: Gavin Wood <gavin@parity.io>

substrate/Cargo.lock

@@ -3942,6 +3942,7 @@ dependencies = [
  "parking_lot 0.10.0",
  "serde",
  "sp-consensus-babe",
+ "sp-consensus-vrf",
  "sp-core",
  "sp-inherents",
  "sp-io",
@@ -5893,6 +5894,7 @@ dependencies = [
  "sp-blockchain",
  "sp-consensus",
  "sp-consensus-babe",
+ "sp-consensus-vrf",
  "sp-core",
  "sp-inherents",
  "sp-io",
@@ -7095,10 +7097,10 @@ name = "sp-consensus-babe"
 version = "0.8.0-alpha.4"
 dependencies = [
  "parity-scale-codec",
- "schnorrkel",
  "sp-api",
  "sp-application-crypto",
  "sp-consensus",
+ "sp-consensus-vrf",
  "sp-inherents",
  "sp-runtime",
  "sp-std",
@@ -7116,6 +7118,17 @@ dependencies = [
  "sp-std",
 ]
 
+[[package]]
+name = "sp-consensus-vrf"
+version = "0.8.0-alpha.4"
+dependencies = [
+ "parity-scale-codec",
+ "schnorrkel",
+ "sp-core",
+ "sp-runtime",
+ "sp-std",
+]
+
 [[package]]
 name = "sp-core"
 version = "2.0.0-alpha.4"