feat: Migration framework (#1768)

This PR implemented the migration framework, which contains the command
line interface to execute migration and helps to migrate data easily.
Please read README.md for more information about this framework.

src/app/CMakeLists.txt

@@ -1,4 +1,4 @@
 add_library(clio_app)
 target_sources(clio_app PRIVATE CliArgs.cpp ClioApplication.cpp WebHandlers.cpp)
 
-target_link_libraries(clio_app PUBLIC clio_etl clio_etlng clio_feed clio_web clio_rpc)
+target_link_libraries(clio_app PUBLIC clio_etl clio_etlng clio_feed clio_web clio_rpc clio_migration)

src/app/CliArgs.cpp

@@ -19,6 +19,7 @@
 
 #include "app/CliArgs.hpp"
 
+#include "migration/MigrationApplication.hpp"
 #include "util/build/Build.hpp"
 
 #include <boost/program_options/options_description.hpp>
@@ -45,6 +46,7 @@ CliArgs::parse(int argc, char const* argv[])
         ("version,v", "print version and exit")
         ("conf,c", po::value<std::string>()->default_value(defaultConfigPath), "configuration file")
         ("ng-web-server,w", "Use ng-web-server")
+        ("migrate", po::value<std::string>(), "start migration helper")
     ;
     // clang-format on
     po::positional_options_description positional;
@@ -65,6 +67,14 @@ CliArgs::parse(int argc, char const* argv[])
     }
 
     auto configPath = parsed["conf"].as<std::string>();
+
+    if (parsed.count("migrate") != 0u) {
+        auto const opt = parsed["migrate"].as<std::string>();
+        if (opt == "status")
+            return Action{Action::Migrate{std::move(configPath), MigrateSubCmd::status()}};
+        return Action{Action::Migrate{std::move(configPath), MigrateSubCmd::migration(opt)}};
+    }
+
     return Action{Action::Run{.configPath = std::move(configPath), .useNgWebServer = parsed.count("ng-web-server") != 0}
     };
 }

src/app/CliArgs.hpp

@@ -19,6 +19,7 @@
 
 #pragma once
 
+#include "migration/MigrationApplication.hpp"
 #include "util/OverloadSet.hpp"
 
 #include <string>
@@ -52,13 +53,20 @@ public:
             int exitCode;  ///< Exit code.
         };
 
+        /** @brief Migration action. */
+        struct Migrate {
+            std::string configPath;
+            MigrateSubCmd subCmd;
+        };
+
         /**
          * @brief Construct an action from a Run.
          *
          * @param action Run action.
          */
         template <typename ActionType>
-            requires std::is_same_v<ActionType, Run> or std::is_same_v<ActionType, Exit>
+            requires std::is_same_v<ActionType, Run> or std::is_same_v<ActionType, Exit> or
+            std::is_same_v<ActionType, Migrate>
         explicit Action(ActionType&& action) : action_(std::forward<ActionType>(action))
         {
         }
@@ -78,7 +86,7 @@ public:
         }
 
     private:
-        std::variant<Run, Exit> action_;
+        std::variant<Run, Exit, Migrate> action_;
     };
 
     /**