Improve documentation to explain how to create an API key and save it in the settings about headscale-ui

[routerino]

Missing bearer prefix means that the API key is either missing or malformed. Have you generated an API key in headscale and saved it to your settings? If so, there may be a problem with your proxy config.

[routerino]

closing unless/until problem can be recreated.

[Sloth-on-meth]

same error here, even though api key is created and shows up when i list them

[routerino]

what browser and version of headscale are you using? Did you actually copy the API key to the headscale UI settings and save?

[routerino]

When updating the documentation, also add the tooltip explaning localStorage back to "save api key", as it got lost when shuffling around the button settings.