Add ability to pass additional options to postgrest

[fzaninotto]

Problem

PostGREST exposes a config option that ra-supabase doesn't expose: sort order.

We could add a new parameter if it in the ra-supabase data provider constructor, but each time postgrest adds new configs, we'll need to update ra-supabase, too.

Solution

Add support for all possible postgrest config options, present and future, via a rest parameter