Zombienet tests - disputes on finalized blocks (#2184)

**Overview:**
Adding an extra malus variant focusing on disputing finalized blocks. It
will:
- wrap around approval-voting
- listen to `OverseerSignal::BlockFinalized` and when encountered start
a dispute for the `dispute_offset`th ancestor
- simply pass through all other messages and signals

Add zombienet tests testing various edgecases:
- disputing freshly finalized blocks
- disputing stale finalized blocks
- disputing eagerly pruned finalized blocks (might be separate PR)

**TODO:**
- [x] Register new malus variant
- [x] Simple pass through wrapper (approval-voting)
- [x] Simple network definition
- [x] Listen to block finalizations
- [x] Fetch ancestor hash
- [x] Fetch session index
- [x] Fetch candidate
- [x] Construct and send dispute message
- [x] zndsl test 1 checking that disputes on fresh finalizations resolve
valid Closes #1365
- [x] zndsl test 2 checking that disputes for too old finalized blocks
are not possible Closes #1364
- [ ] zndsl test 3 checking that disputes for candidates with eagerly
pruned relay parent state are handled correctly #1359 (deferred to a
separate PR)
- [x] Unit tests for new malus variant (testing cli etc)
- [x] Clean/streamline error handling
- [ ] ~~Ensure it tests properly on session boundaries~~

---------

Co-authored-by: Javier Viola <javier@parity.io>
Co-authored-by: Marcin S. <marcin@realemail.net>
Co-authored-by: Tsvetomir Dimitrov <tsvetomir@parity.io>

.gitlab/pipeline/zombienet/polkadot.yml

@@ -115,6 +115,22 @@ zombienet-polkadot-functional-0006-parachains-max-tranche0:
       --local-dir="${LOCAL_DIR}/functional"
       --test="0006-parachains-max-tranche0.zndsl"
 
+zombienet-polkadot-functional-0007-dispute-freshly-finalized:
+  extends:
+    - .zombienet-polkadot-common
+  script:
+    - /home/nonroot/zombie-net/scripts/ci/run-test-local-env-manager.sh
+      --local-dir="${LOCAL_DIR}/functional"
+      --test="0007-dispute-freshly-finalized.zndsl"
+
+zombienet-polkadot-functional-0008-dispute-old-finalized:
+  extends:
+    - .zombienet-polkadot-common
+  script:
+    - /home/nonroot/zombie-net/scripts/ci/run-test-local-env-manager.sh
+      --local-dir="${LOCAL_DIR}/functional"
+      --test="0008-dispute-old-finalized.zndsl"
+
 zombienet-polkadot-smoke-0001-parachains-smoke-test:
   extends:
     - .zombienet-polkadot-common