docs: workspace (type) documentation is outdated

[embik]

Describe the bug

Our docs at https://docs.kcp.io/kcp/v0.26/concepts/workspaces/ seem really really outdated:

1. The workspace type reference in the example YAML is no longer valid as far as I can say from the spec.
2. We don't document workspace type references at all, making it clear that they can be cross-workspaced AND require RBAC (see https://github.com/kcp-dev/kcp/blob/main/config/root/clusterrole-workspacetype-use.yaml for an example).
3. Do home workspaces even work the way they're documented? Are buckets still a thing? I don't seem to see a "full path" when I use a home workspace, just a logical cluster name.

Steps To Reproduce

1. Go to docs and try to make sense of them.

Expected Behaviour

Docs should reflect the current situation and document how to use things.

Additional Context

Slack thread reference.

[xmudrii]

/assign

[kcp-ci-bot]

Issues go stale after 90d of inactivity.
After a furter 30 days, they will turn rotten.
Mark the issue as fresh with /remove-lifecycle stale.

If this issue is safe to close now please do so with /close.

/lifecycle stale

[xmudrii]

/remove-lifecycle stale

[kcp-ci-bot]

Issues go stale after 90d of inactivity.
After a furter 30 days, they will turn rotten.
Mark the issue as fresh with /remove-lifecycle stale.

If this issue is safe to close now please do so with /close.

/lifecycle stale

[xmudrii]

/remove-lifecycle stale
/unassign
not working at this at the moment