perf(screenshot): optimize the screenshot code && add print and download

[QFifteen]

General

✏️ Mark the necessary items without changing the structure of the PR template.

• Pull request template structure not broken

Type

ℹ️ What types of changes does your code introduce?

👉 Put an x in the boxes that apply

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

Checklist

ℹ️ Check all checkboxes - this will indicate that you have done everything in accordance with the rules in CONTRIBUTING.

👉 Put an x in the boxes that apply.

• My code follows the style guidelines of this project
• Is the code format correct
• Is the git submission information standard?
• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules

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此pr主要是对截图模块的优化及扩展，主要改动为：

• 截图示例模块的布局微调、优化部分代码
• 新增打印截图，下载截图功能

打印截图功能的需求会出现在G端(政府端)业务上，比如行政通知单、执法单、报告单等，这里的打印截图功能可以满足粗粒度的打印功能

现在，截图模块是这样的：