client/authority-discovery: Allow to be run by sentry node (#5568)

* client/authority-discovery: Allow to be run by sentry node

When run as a sentry node, the authority discovery module does not
publish any addresses to the dht, but still discovers validators and
sentry nodes of validators.

* client/authority-discovery/src/lib: Wrap lines at 100 characters

* client/authority-discovery: Remove TODO and unused import

* client/authority-discovery: Pass role to new unit tests

* client/authority-discovery: Apply suggestions

Co-Authored-By: André Silva <123550+andresilva@users.noreply.github.com>

* bin/node/cli/src/service: Use expressions instead of statements

Co-authored-by: André Silva <123550+andresilva@users.noreply.github.com>

substrate/.maintain/sentry-node/docker-compose.yml

@@ -82,13 +82,12 @@ services:
       - "--chain=local"
       - "--port"
       - "30333"
-      - "--charlie"
       - "--sentry"
       - "/dns4/validator-a/tcp/30333/p2p/QmRpheLN4JWdAnY7HGJfWFNbfkQCb6tFf4vvA6hgjMZKrR"
+      - "--reserved-nodes"
+      - "/dns4/validator-a/tcp/30333/p2p/QmRpheLN4JWdAnY7HGJfWFNbfkQCb6tFf4vvA6hgjMZKrR"
       - "--bootnodes"
       - "/dns4/validator-b/tcp/30333/p2p/QmSVnNf9HwVMT1Y4cK1P6aoJcEZjmoTXpjKBmAABLMnZEk"
-      - "--reserved-nodes"
-      - "/dns4/validator-a/tcp/30333/p2p/QmRpheLN4JWdAnY7HGJfWFNbfkQCb6tFf4vvA6hgjMZKrR"
       - "--no-telemetry"
       - "--rpc-cors"
       - "all"
@@ -97,7 +96,6 @@ services:
       - "--unsafe-rpc-external"
       - "--log"
       - "sub-authority-discovery=trace"
-      - "--sentry"
       - "--prometheus-external"
 
   validator-b: