Node-side subsystems for Disputes (#2566)

* dispute subsystem files

* rename

* fix linkcheck

* flesh out section README

* coordinator schema

* DisputeCoordinatorMessage

* stub & coordinator protocol

* dispute coordinator

* add some more message fields

* move links to bottom

* dispute participation

* Cleen It Up !

* runtime: store candidate receipts in dispute state

yeah, this is a little heavier. why are you reading this?

* Revert "runtime: store candidate receipts in dispute state"

This reverts commit 51c10bfd4d866e287e6bd88f317ed57ed987eaee.

* add dispute availability statement type and prepare for availability

* add 'spam slots' to disputes runtmie

* return Spam Slots info from runtime

* rework `ImportStatement` to `ImportStatements`

* some more methods for dispute coordinator

* candidates-included runtime API

* algo for providing disputes to runtime.

* handle signing with coordinator

* dispute coordinator chain ops

* remove dead file

* remove keystore from dispute participation

* adjust ApprovedAncestor to return the necssary data

* discuss how approved ancestor and determine undisputed chain are used together

* add TODO

* initiate disputes from approval voting

* route statements from candidate backing and approval voting

* fix guide build

polkadot/roadmap/implementers-guide/src/SUMMARY.md

@@ -30,7 +30,8 @@
   - [Validation Code](runtime-api/validation-code.md)
   - [Candidate Pending Availability](runtime-api/candidate-pending-availability.md)
   - [Candidate Events](runtime-api/candidate-events.md)
-  - [Known Disputes](runtime-api/known-disputes.md)
+  - [Disputes Info](runtime-api/disputes-info.md)
+  - [Candidates Included](runtime-api/candidates-included.md)
 - [Node Architecture](node/README.md)
   - [Subsystems and Jobs](node/subsystems-and-jobs.md)
   - [Overseer](node/overseer.md)
@@ -51,7 +52,10 @@
   - [Approval Subsystems](node/approval/README.md)
     - [Approval Voting](node/approval/approval-voting.md)
     - [Approval Distribution](node/approval/approval-distribution.md)
-    - [Dispute Participation](node/approval/dispute-participation.md)
+  - [Disputes Subsystems](node/disputes/README.md)
+    - [Dispute Coordinator](node/disputes/dispute-coordinator.md)
+    - [Dispute Participation](node/disputes/dispute-participation.md)
+    - [Dispute Distribution](node/disputes/dispute-distribution.md)
   - [Utility Subsystems](node/utility/README.md)
     - [Availability Store](node/utility/availability-store.md)
     - [Candidate Validation](node/utility/candidate-validation.md)