Add a flag to enable shadow db on supabase start #4936
Description
Is your feature request related to a problem? Please describe.
It would be good to have a way to start up the shadow db via a flag or a command as and when needed. I am using a tool like pgschema which uses a plandb to do it's diffing and currently I have to setup two local supabase projects in order to handle the diffing where as if there was a way to use the shadow db it would be less configurations.
Describe the solution you'd like
There is a PR opened asking for similar thing but only for tests, but this would go a long way if it was able to be a standalone command or flag you can run #4871
Describe alternatives you've considered
Separate local instances
Additional context
Add any other context or screenshots about the feature request here.