Run Web UI Functional Tests on a remote instance

FT for Web UI 2.4 (for Nuxeo 10.10) are in https://github.com/nuxeo/plugin-nuxeo-web-ui (branch 2.4_10.10: https://github.com/nuxeo/plugin-nuxeo-web-ui/tree/2.4_10.10)

Documentation is available at https://doc.nuxeo.com/nxdoc/web-ui-functional-testing/

The test framework, which is composed of a test runner + page helpers + Cucumber step definitions (for BDD) lives in the "nuxeo-web-ui-ftest" folder.

The default tests themselves are in the "ftest/web-ui/webdriver" folder and these can be ran with just `npx nuxeo-web-ui-ftest`, assuming there's already a running Nuxeo instance there's no need for maven of nuxeo-ftest.

Making it possible to ran tests against a remove server was already done in master (see NXP-27288) but not backported yet. I'm including a sample patch webui.diff that would allow you to do:

> npx nuxeo-web-ui-ftest --nuxeoUrl=https://nightly.nuxeo.com/nuxeo/

Also added NUXEO_ADMINISTRATOR_USER and NUXEO_ADMINISTRATOR_PASSWORD environment variables if needed so you could do:

> NUXEO_ADMINISTRATOR_PASSWORD=verysecret NUXEO_URL=... npx nuxeo-web-ui-ftest

NB: FT for Web UI 3.0.0 (for Nuxeo 11.1) have been moved to https://github.com/nuxeo/nuxeo-web-ui/tree/master/ftest