[FEATURE] Faster OAUTH_AUTO_REDIRECT

[MitPitt]

Is your feature request related to a problem? Please describe.
When enabling OAUTH_AUTO_REDIRECT=generic, tinyauth automatically redirects login to oauth provider. But there is a flash of default tinyauth login before the redirect actually happens. This results in suboptimal loading time and it doesn't look very pretty.

Describe the solution you'd like
Redirect straight to auth without showing the default tinyauth login html.
I know this is possible because I've been using caddy-security plugin. It also has an automatic oauth redirect option, and it is instant.

[steveiliop56]

Hello,

Thank you for the suggestion, I could indeed implement the redirect in the backend (as caddy security probably does) to speed up things a bit.

[steveiliop56]

Looking further into this, unfortunately it's not possible to do the redirection server side. This is because it would break proxies like Nginx who handle the redirect themselves. In #355, I made the redirect a bit more pretty by showing an informational message that you are being redirected instead of just showing the login screen and the toast. Hopefully this will make things feel a bit more smooth.