cmd/tailscale/cli: update docs and unhide configure

Also call out Alpha.

Updates #7220

Signed-off-by: Maisem Ali <maisem@tailscale.com>
This commit is contained in:
Internal Server Error - Gitea: Git with a cup of tea
500 Internal Server Error

Gitea Version: 1.28.0+dev-477-g8b6ad49a5f