Secure e-mail change - request password confirmation

When changing e-mail: • If secure e-mail change is disabled, Supabase will send an e-mail to the new e-mail address. This option isn't secure, as it allows change an e-mail as long as adversary has access to the user session (e.g. when user forgot to lock computer when going for a cup of coffee). • If secure e-mail change is enabled, Supabase will send an e-mail to both new and old e-mail address. This is secure, the issue is that if user no longer has access to the old e-mail they're forced to use inactive e-mail during login and it's only a matter of time when they will lock themselves out (e.g when they forget password to the Supabase account) without any option to retrieve their login data. This happens especially when they try to login to account which wasn't active for quite a while. User themselves might've already migrated away from the old e-mail address to the new e-mail address without realizing that they haven't changed th…