Remove backup signature stuff (#6476)

Co-authored-by: Amaury Chamayou <amchamay@microsoft.com>

src/kv/kv_types.h

@@ -399,10 +399,6 @@ namespace ccf::kv
     };
 
     virtual ~TxHistory() {}
-    virtual Result verify_and_sign(
-      ccf::PrimarySignature& signature,
-      Term* term,
-      ccf::kv::Configuration::Nodes& nodes) = 0;
     virtual bool verify_root_signatures() = 0;
     virtual void try_emit_signature() = 0;
     virtual void emit_signature() = 0;

src/node/history.h

@@ -152,14 +152,6 @@ namespace ccf
       version++;
     }
 
-    ccf::kv::TxHistory::Result verify_and_sign(
-      PrimarySignature&,
-      ccf::kv::Term*,
-      ccf::kv::Configuration::Nodes&) override
-    {
-      return ccf::kv::TxHistory::Result::OK;
-    }
-
     bool verify_root_signatures() override
     {
       return true;
@@ -703,24 +695,6 @@ namespace ccf
         term_of_next_version};
     }
 
-    ccf::kv::TxHistory::Result verify_and_sign(
-      PrimarySignature& sig,
-      ccf::kv::Term* term,
-      ccf::kv::Configuration::Nodes& config) override
-    {
-      if (!verify_root_signatures())
-      {
-        return ccf::kv::TxHistory::Result::FAIL;
-      }
-
-      ccf::kv::TxHistory::Result result = ccf::kv::TxHistory::Result::OK;
-
-      sig.node = id;
-      sig.sig = node_kp.sign_hash(sig.root.h.data(), sig.root.h.size());
-
-      return result;
-    }
-
     bool verify_root_signatures() override
     {
       auto tx = store.create_read_only_tx();

src/service/network_tables.h

@@ -21,7 +21,6 @@
 #include "ccf/service/tables/users.h"
 #include "ccf/service/tables/uvm_endorsements.h"
 #include "kv/store.h"
-#include "tables/backup_signatures.h"
 #include "tables/config.h"
 #include "tables/governance_history.h"
 #include "tables/previous_service_identity.h"