Add a second static page for slack.brigade.sh

[krancour]

For some time now, https://slack.brigade.sh has redirected users to our Slack channel. If you're not signed into Slack in your browser, you see this:

For those of us very familiar with the project, this isn't confusing. We know that our Slack channel is part of the Kubernetes Slack workspace, but for people very new to the project who lack that context, this is like running into a brick wall -- probably in part because there's nothing on that page that tells you how to get an invite to the Kubernetes workspace. That's over at http://slack.kubernetes.io. This has tripped up at least three people (that I know of) in the past week alone.

What I'd like to do is develop a simple, static page that https://slack.brigade.sh can be pointed to in the future and this page can succinctly explain that you need to join the Kubernetes workspace and then join our channel. We can have links to get your Kubernetes workspace invite as well as the link directly to our channel.

I think we can also make the link to our channel open in the Slack client instead of the web browser, if you have it installed.

I can't see much point in deploying a whole separate site for slack.brigade.sh. Instead, I propose adding a second static page to this site, and it will live at https://brigade.sh/slack. I can update Azure Front Door configuration to redirect request from https://slack.brigade.sh to https://brigade.sh/slack.

Any thoughts, questions, concerns from @vdice or @flynnduism ?

[vdice]

Sounds good to me!