pallet-collective: allow customized default vote (#6984)

* collective: add DefaultVote trait

* Fix test and node compile

* Expose the whole prime_vote

* Add test for MoreThanMajorityThenPrimeDefaultVote

* Docs fix

substrate/bin/node/runtime/src/lib.rs

@@ -109,7 +109,7 @@ pub const VERSION: RuntimeVersion = RuntimeVersion {
 	// and set impl_version to 0. If only runtime
 	// implementation changes and behavior does not, then leave spec_version as
 	// is and increment impl_version.
-	spec_version: 258,
+	spec_version: 259,
 	impl_version: 0,
 	apis: RUNTIME_API_VERSIONS,
 	transaction_version: 1,
@@ -520,6 +520,7 @@ impl pallet_collective::Trait<CouncilCollective> for Runtime {
 	type MotionDuration = CouncilMotionDuration;
 	type MaxProposals = CouncilMaxProposals;
 	type MaxMembers = CouncilMaxMembers;
+	type DefaultVote = pallet_collective::PrimeDefaultVote;
 	type WeightInfo = weights::pallet_collective::WeightInfo;
 }
 
@@ -569,6 +570,7 @@ impl pallet_collective::Trait<TechnicalCollective> for Runtime {
 	type MotionDuration = TechnicalMotionDuration;
 	type MaxProposals = TechnicalMaxProposals;
 	type MaxMembers = TechnicalMaxMembers;
+	type DefaultVote = pallet_collective::PrimeDefaultVote;
 	type WeightInfo = weights::pallet_collective::WeightInfo;
 }