[curve_ops_tool]: add create/delete directory

[Cyber-SiKu]

Is your feature request related to a problem? (你需要的功能是否与某个问题有关?)

We want to add corresponding operations to directories in create/delete of curve_ops_tool.

• curve_ops_tool create is defined here:
  

  curve/src/tools/namespace_tool.cpp

  Lines 124 to 127 in 7eb8d99

  	} else if (cmd == kCreateCmd) {
  	return core_->CreateFile(fileName, FLAGS_fileLength * mds::kGB,
  	FLAGS_stripeUnit, FLAGS_stripeCount);
  	} else if (cmd == kExtendCmd) {

• curve_ops_tool delete is defined here:
  

  curve/src/tools/namespace_tool.cpp

  Lines 87 to 102 in 7eb8d99

  	} else if (cmd == kDeleteCmd) {
  	// 单元测试不判断输入
  	if (FLAGS_isTest) {
  	return core_->DeleteFile(fileName, FLAGS_forcedelete);
  	}
  	std::cout << "Are you sure you want to delete "
  	<< fileName << "?" << "(yes/no)" << std::endl;
  	std::string str;
  	std::cin >> str;
  	if (str == "yes") {
  	return core_->DeleteFile(fileName, FLAGS_forcedelete);
  	} else {
  	std::cout << "Delete cancled!" << std::endl;
  	return 0;
  	}
  	} else if (cmd == kCleanRecycleCmd) {

• protobuf is defined here:
  

  curve/proto/nameserver2.proto

  Lines 195 to 223 in 7eb8d99

  	message CreateFileRequest {
  	required string fileName = 1;
  	required FileType fileType = 3;
  	optional uint64 fileLength = 4;
  	required string owner = 2;
  	optional string signature = 5;
  	required uint64 date = 6;
  	optional uint64 stripeUnit = 7;
  	optional uint64 stripeCount = 8;
  	};
  	message CreateFileResponse {
  	required StatusCode statusCode = 1;
  	}
  	message DeleteFileRequest {
  	required string fileName = 1;
  	required string owner = 2;
  	optional string signature = 3;
  	required uint64 date = 4;
  	optional uint64 fileId = 5;
  	optional bool forceDelete = 6;
  	};
  	message DeleteFileResponse {
  	required StatusCode statusCode = 1;
  	}

• The output of the command should look like:

curve_ops_tool create -fileType=dir =filename=/test -userName=test -password=123

Describe the solution you'd like (描述你期望的解决方法)

Add a FLAG_TYPE, the default is file, execute the old logic, when the value is dir, set the fileType of the request to INODE_DIRECTORY.

Describe alternatives you've considered (描述你想到的折衷方案)

Additional context/screenshots (更多上下文/截图)