Write screenshot to file

[negiDharmendra]

• Changed default screenshot grabber to write to file and return file path.
• Depricate existing custom screenshot grabber API contract.
• Create a new API contact for custom screenshot grabber to write the screenshot into file and returning file path instead of screenhsot bytes.

from getgauge.python import custom_screenshot_writer

@custom_screenshot_writer
def take_screenshot():
    conetnt = Driver.driver.get_screenshot_as_png()
    file_name = os.path.join(os.getenv("gauge_screenshots_dir"), "screenshot-file.png")
    file = open(file_name, "w")
    file.write(conetnt)
    return os.path.basename(file_name)