chore: remove insecure schema permissions from SQL schema file

Refactors schema setup by commenting out default privilege grants to improve security posture.

Author: jumski

pkgs/core/schemas/0020_schemas.sql

@@ -1,17 +1,2 @@
 -- Create schemas
 create schema if not exists pgflow;
-
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------------------- TODO: fix me, UNSECURE --------------------------------
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--- Commenting out permissions for Atlas diff
--- grant usage on schema pgflow to anon, authenticated, service_role;
--- grant all on all tables in schema pgflow to anon, authenticated, service_role;
--- grant all on all routines in schema pgflow to anon, authenticated, service_role;
--- grant all on all sequences in schema pgflow to anon, authenticated, service_role;
--- alter default privileges for role postgres in schema pgflow
--- grant all on tables to anon, authenticated, service_role;
--- alter default privileges for role postgres in schema pgflow
--- grant all on routines to anon, authenticated, service_role;
--- alter default privileges for role postgres in schema pgflow
--- grant all on sequences to anon, authenticated, service_role;