[curve/toos-v2]: add set-copyset-availflag

[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'd like to support bs set copyset-availflag command in curve tool

• The implementation of the old tool is here：

  curve/src/tools/copyset_tool.cpp

  Lines 38 to 53 in 8d6caf7

  	if (command == kSetCopysetAvailFlag) {
  	google::CommandLineFlagInfo info;
  	if (!GetCommandLineFlagInfo("availFlag", &info)) {
  	std::cout << "availFlag must be specified!" << std::endl;
  	return -1;
  	}
  	if (FLAGS_availFlag) {
  	return SetCopysetsAvailable();
  	} else {
  	return SetCopysetsUnAvailable();
  	}
  	} else {
  	PrintHelp(command);
  	return -1;
  	}
  	}

• The old command input and out put:

curve_ops_tool set-copyset-availflag

-------
output:

Refer to tool develop guide to get start, and paste the result of the command in pr.

Build compilation environment：https://github.com/opencurve/curve/blob/master/docs/cn/build_and_run.md

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

Add subcommand clinet to curve bs list.

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)

[zhanghuidinah]

• This issue has been chosen for community developer activities. Welcome to feel free to try it. After the PR is merged, you will receive a gift package and a certificate as a community contributor.

• Developer Activities Registration Steps please ref [2023 Q2 Developer Activities]: Call For Participation！ #2334 (comment)

[baytan0720]

I want to try it

[Cyber-SiKu]

@baytan0720

I want to try it

done