babe: treat epoch_authorship RPC method as unsafe (#6069)

* service: pass DenyUnsafe to rpc extensions

* node: add DenyUnsafe to rpc full node dependencies

* client: fix whitespace in rpc policy file

* babe: treat epochAuthorship rpc method as unsafe

* babe: add test for unsafe rpc method

* babe: rename babe rpc handler

* service: traitify rpc extension builder

* service: make the rpc extensions builder api non-breaking

* service: revert changes from light node rpc extensions builder

* node: remove unnecessary type in service creation

* service: cleanup with_rpc_extensions implementation

* service: add missing docs to RpcExtensionBuilder

substrate/Cargo.lock

@@ -3567,6 +3567,7 @@ dependencies = [
  "sc-finality-grandpa",
  "sc-finality-grandpa-rpc",
  "sc-keystore",
+ "sc-rpc-api",
  "sp-api",
  "sp-blockchain",
  "sp-consensus",
@@ -6165,10 +6166,13 @@ dependencies = [
  "jsonrpc-core",
  "jsonrpc-core-client",
  "jsonrpc-derive",
+ "sc-consensus",
  "sc-consensus-babe",
  "sc-consensus-epochs",
  "sc-keystore",
+ "sc-rpc-api",
  "serde",
+ "serde_json",
  "sp-api",
  "sp-application-crypto",
  "sp-blockchain",