Redirect to localhost instead of e2b.dev after sign in with oauth in dev environment (e2b-dev#499)

this pr fixes the following in a local development environment:

- supabase auth redirect after oauth sign in
- forgot password flow


this is accomplished by adding a new environment variable
`NEXT_PUBLIC_BASE_URL` which prevents checking something like
`process.env.NODE_ENV` and conditionally hardcoding the urls in the code
itself. this way, for potential changes to these values, we can utilise
this mechanic in other places where it may be required in the near
future without traversing the codebase manually.

i already set `NEXT_PUBLIC_BASE_URL` in the vercel production
environment to: `https://e2b.dev`

Author: ben-fornefeld

apps/web/src/components/AuthForm.tsx

@@ -72,8 +72,8 @@ function AuthForm({ view }: Props) {
           }}
           redirectTo={
             view === 'forgotten_password'
-              ? 'https://e2b.dev/auth/update-password'
-              : 'https://e2b.dev/dashboard'
+              ? `${document.location.origin}/auth/update-password`
+              : `${document.location.origin}/dashboard`
           }
         />
       </div>