Devfile metadata: add a link to an external website

[deboer-tim]

When you use a devfile in an IDE, the IDE might want to be able to display a devfile-specific welcome page. Likewise, a command line tool might want to link to information on how to use the devfile. In both of these cases we want the devfile to provide the link and not pull other files into the user's project, which could be easily removed or annoying to clean up.

For cases like these it would be nice to have an optional doc url in the devfile metadata.

[l0rd]

We are going to add the website metadata at the top level of the devfile:

---
schemaVersion: 2.0.0
metadata:
  name: quarkus-stack
  description: ...
  website: https://quarkus.io

[l0rd]

@deboer-tim if that's satisfies your need we are going to add that to the spec

[deboer-tim]

+1. I don't love 'website', but I can't decide why or come up with a better option, so let's go with it. :)

[l0rd]

Yes we named it website because it includes but is broader then documentation.