allure plugin for robotframework-seleniumlibrary

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This could be an good example or part of a robot adapter
```python
import allure
from SeleniumLibrary import ScreenshotKeywords
from SeleniumLibrary.base import keyword, LibraryComponent

class AllureSeleniumPlugin(LibraryComponent):

@keyword
def capture_page_screenshot(self, filename='selenium-screenshot-{index}.png'):
path = ScreenshotKeywords(ctx=self.ctx).capture_page_screenshot(filename)
allure.attach.file(path, attachment_type=allure.attachment_type.PNG)
```

```robot
Library SeleniumLibrary plugins=AllureSeleniumPlugin
```

Inizia con l’esempio Python AllureSeleniumPlugin proposto e il suo punto di ingresso capture_page_screenshot. Verifica come l’impostazione di Robot Framework Library passi plugins=AllureSeleniumPlugin, quindi determina l’ambito richiesto dell’integrazione. Done dovrebbe fornire un plugin SeleniumLibrary utilizzabile che alleghi gli screenshot delle pagine acquisiti ai report Allure.

Scritto dal modello di indicizzazione a partire dal testo della issue.