Add a new widget and a new feature

[TempAccountOfMuxue1230]

PR Summary

This change provides a new button IconOnlyButton, which allows development to place a separate icon only button on the interface.
此更改提供了一个新的按钮IconOnlyButton，这使得开发时可以在界面上放置一个单独的纯图标按钮。
Below are examples:
以下是示例：

Extra Information

This button is not very commonly used, but it is still very handy in some cases.
这个按钮虽然不是非常常用，但部分情况下还是非常方便的。

PR Checklist

• The PR doesn't duplicate another PR which is already open

• "closes #0000" is in the body of the PR description to link the related issue

• New or changed code has been tested

• When it comes to API modifications, the docstrings of related classes or functions are also modified

• I have read the contribution guide and followed all the instructions

[codecov]

Codecov Report

Attention: Patch coverage is 22.58065% with 24 lines in your changes missing coverage. Please review.

✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
maliang/standard/features.py	17.64%	14 Missing ⚠️
maliang/standard/widgets.py	28.57%	10 Missing ⚠️

Files with missing lines	Coverage Δ
maliang/standard/widgets.py	23.52% <28.57%> (+0.13%)	⬆️
maliang/standard/features.py	25.07% <17.64%> (-0.40%)	⬇️

[Xiaokang2022]

Button 手动指定大小，并指定 image 参数时，不就和你这个类的功能差不多吗？

有没有一种可能，不需要新增控件，优化原有的就行？还是说，你这个有什么特殊的地方？

[TempAccountOfMuxue1230]

我去掉了外壳，也就是说Feature必须更改

[TempAccountOfMuxue1230]

[Xiaokang2022]

我去掉了外壳，也就是说Feature必须更改

有没有一种可能，外壳可以直接通过指定 style 参数来隐藏呢？

[TempAccountOfMuxue1230]

Feature会报错

[TempAccountOfMuxue1230]

隐藏我直接是这样的

[TempAccountOfMuxue1230]

这个时候feature必须改成这样：

[Xiaokang2022]

我有个想法，不如随着“典型自定义”的那几个控件，一起移动到扩展包里去吧？

https://xiaokang2022.github.io/maliang-docs/3.0/tutorials/chapter_03/2/#%E4%B8%89%E5%85%B8%E5%9E%8B%E8%87%AA%E5%AE%9A%E4%B9%89%E6%8E%A7%E4%BB%B6

详细内容见上面链接的中的橙色警告提示框。

[TempAccountOfMuxue1230]

可以的

[Xiaokang2022]

正式版前不考虑添加新控件，正式版之后再处理该 PR