Add Admin routes

[lescuer97]

Add admin routes and login page.

We will use golang templates and htmx for actions to the server and NDK for nostr.

for the login page it would be cool if we could use nostr for it. This way we don't have a password based way of authentication.

if there is no nostr pubkey set for login it should notify the user that you need to set that up first.

After login happens all request should go through a middleware that checks for cookie authorization sent by the server after successful login.

[lescuer97]

done