show list of sub-accounts for given account

[amgando]

this seems like a useful view
https://stackoverflow.com/questions/70957793/is-there-a-way-to-list-all-the-subaccounts-my-account-have

[Bexanderthebex]

@amgando cool, I'll see what I can do with postgres as we are already hitting limits with the current amount of data and it might not be as easy as it looks if we want to make it quick and return as fast as possible. But we can make something the works for the moment.