Remove old service, 3rd try (#1776)

* Remove old service, 3rd try

i.e.
Revert "Revert "Remove Old Service, 2nd try (#1732)" (#1758)"

This reverts commit 9a0f08bfe1.

Closes #1757.

We now have some evidence that the polkadot validator was producing
blocks after all; the reason the blocks_constructed metric was 0 was
that as a new metric it hadn't yet been incorporated into that
branch's codebase. See
https://github.com/paritytech/polkadot/issues/1757#issuecomment-700977602

As this PR is based on a newer `master` branch than the previous one,
that should hopefully no longer be an issue.

* paras trait now has an Origin type

* initial work running a two node local net

* use the right incantations so the nodes produce blocks together

* improve internal documentation

Co-authored-by: Bastian Köcher <git@kchr.de>

polkadot/runtime/westend/src/lib.rs

@@ -23,9 +23,9 @@
 use sp_std::prelude::*;
 use codec::{Encode, Decode};
 use primitives::v1::{
-	AccountId, AccountIndex, Balance, BlockNumber, Hash, Nonce, Signature, Moment, ValidatorId,
-	ValidatorIndex, CoreState, Id, CandidateEvent, ValidationData, OccupiedCoreAssumption,
-	CommittedCandidateReceipt, PersistedValidationData, GroupRotationInfo, ValidationCode,
+	AccountId, AccountIndex, Balance, BlockNumber, CandidateEvent, CommittedCandidateReceipt,
+	CoreState, GroupRotationInfo, Hash, Id, Moment, Nonce, OccupiedCoreAssumption,
+	PersistedValidationData, Signature, ValidationCode, ValidationData, ValidatorId, ValidatorIndex,
 };
 use runtime_common::{
 	SlowAdjustingFeeUpdate,