Remove visual samples index

[ericwindmill]

Removes VSI and all related infra. It has been replaced by an index page on flutter.dev

Fixes:

#2582
#2507

Pre-launch Checklist

• I read the [Flutter Style Guide] recently, and have followed its advice.
• I signed the [CLA].
• I read the [Contributors Guide].
• I have added sample code updates to the [changelog].
• I updated/added relevant documentation (doc comments with ///).

[johnpryan]

Does this include a redirect to the new page?

[ericwindmill]

Does this include a redirect to the new page?

If I understand gh pages correctly (which I might not), would it be easier to add the redirect to the gh pages repo? I made a PR, but I'm unsure if it also requires adding something to this repo. flutter/flutter.github.io#2

[johnpryan]

I'm not sure. The previous tooling published to https://flutter.github.io/samples by using the gh-pages branch, so I was expecting this PR to add a page that redirects to the new samples page, not just flutter.dev

[ericwindmill]

I'm not sure. The previous tooling published to https://flutter.github.io/samples by using the gh-pages branch, so I was expecting this PR to add a page that redirects to the new samples page, not just flutter.dev

Right now the main ghpages repo redirects to the gh pages set up here when the user navigates to /samples, so when we update that repo, it should just ignore this repo altogether. Because we're in an organization, the base ghpages has to be it's own repo.

I also don't have permissions to see or update settings for this repository, so I'm unsure if we need to flip a bit there. @domesticmouse, do you have permissions?

[johnpryan]

Hmm, maybe we need an administrator to unpublish this site so that we can redirect /samples to the new docs page (flutter/flutter.github.io#2)

[johnpryan]

That said, I think it's okay to merge this PR and verify the behavior afterwards.