Support OAuth or OIDC connectivity for Tailscale

[justin8]

Currently the tailscale extension requires an auth key, which has a maximum lifespan of 90 days and can be quite painful to manage. It'd be very useful for anyone using Tailscale with Talos to use either an OAuth clientId/clientSecret generated within Tailscale or identity federation via OIDC.

[astlock]

Actually, this is already supported because the Tailscale binary itself allows using an OAuth Client Secret directly in the --auth-key flag.

You can simply use your OAuth Client Secret into TS_AUTHKEY, no changes are needed.

https://tailscale.com/docs/features/oauth-clients#register-new-nodes-using-oauth-credentials

[justin8]

That is very unexpected, but at least it's simple and straightforward I suppose, I'll give it a go and maybe make a PR to update the documentation for the extension then.