Database helper/var for edge functions domain

[Revadike]

It would be nice for supabase to have an out-of-box variable or getter function that return the edge functions domain, depending on the environment.
So for production it would return https://myprojectid.supabase.co/functions/v1/ and in a local environment it would return http://127.0.0.1:54321/functions/v1/.
Alternatively, you just return the domain (without /functions/v1/)
This would be incredibly helpful to test out cron job or webhooks with edge functions.