feat: Snapshot exporting tool (#1877)

In this PR:
1 We create a golang grpc client to request data from rippled
2 We store the data into the specific place
3 Add unittests
4 Create build script, the build can be initiated by set conan option
`snapshot` being true.

Please ignore the grpc server part. It will be implemented in importing
tool.

CMakeLists.txt

@@ -16,6 +16,8 @@ option(coverage "Build test coverage report" FALSE)
 option(packaging "Create distribution packages" FALSE)
 option(lint "Run clang-tidy checks during compilation" FALSE)
 option(static "Statically linked Clio" FALSE)
+option(snapshot "Build snapshot tool" FALSE)
+
 # ========================================================================== #
 set(san "" CACHE STRING "Add sanitizer instrumentation")
 set(CMAKE_EXPORT_COMPILE_COMMANDS TRUE)
@@ -91,3 +93,7 @@ include(install/install)
 if (packaging)
   include(cmake/packaging.cmake) # This file exists only in build runner
 endif ()
+
+if (snapshot)
+  add_subdirectory(tools/snapshot)
+endif ()