Remove non-functional /signup endpoint

[rancher-max]

Is your feature request related to a problem? Please describe.

There exists a /signup endpoint by default in v2.10.1 (and earlier versions) that doesn't actually do anything. It appears that it is a public signup URL to manage the rancher instance or cluster, where people can submit a name and email, but no email actually arrives to register.

Describe the solution you'd like

We should remove this endpoint.

Describe alternatives you've considered

N/A

Additional context

[richard-cox]

We should investigate where this came in and understand if it could still be in use, also the state of the rancher (assuming this wasn't something previously removed from the ui) endpoint it's calling

[rancher-max]

I tried in fresh installs both in docker setup and HA with valid certs and in both of those cases, at least, it was essentially non-functional. Your point stands though that it may require some additional configurations and then becomes functional, so more investigation definitely needed.

[richard-cox]

More on slack, but summarising...

• Multiple new UI pages came in via User registration system ui#1023
  • signup
  • verify
  • verify-reset-password
• Pages make requests to two endpoints
  • /register-new
  • /verify-token
• Still not sure where this feature was used, but if those endpoints don't exist anywhere we should be safe to remove at least signup and probably the other two