Protractortest.org should have a deprecation notice on the homepage

[askeric]

This upcoming reduced support for protractor should be mentioned on the protractor homepage https://www.protractortest.org/#/ (or other major entrypoints) so as to not lead people down the wrong path.

See #5502

[StanislavKharchenko]

I think Angular team should publish their vision about Protractor support and it’s shared ownerships with other companies as it was described in last comment of mentioned rfc.