Screenshots in PhantomJS tests

[yelizariev]

https://itpp.dev/test/unittests/js/phantomjs-screenshots.html

--screenshots
Specify directory where to write screenshots when an HttpCase.browser_js test fails. It defaults to /tmp/odoo_tests/db_name/screenshots

--screencasts
Enable screencasts and specify directory where to write screencasts files. The ffmpeg utility needs to be installed to encode frames into a video file. Otherwise frames will be kept instead of the video file.

In 13+ https://www.odoo.com/documentation/13.0/reference/cmdline.html