feat: filter top-level resource with embed filter

This is enabled by adding `!inner` to the embedded resource

/projects?select=*,clients!inner(*)&clients.id=eq.12

This behaviour can be enabled by default with the config option

db-embed-default-join='inner'

Which saves the need for specifying `!inner` on every request.
If this is enabled, the previous behavior can be restored
per request by specifying `!left`  on the embedded resource.

/projects?select=*,clients!left(*)&clients.id=eq.12`

Tested on M20/02M/M2M relationships, views, RPC.

test/fixtures/data.sql

@@ -691,4 +691,19 @@ DO $do$BEGIN
     INSERT INTO test.reference_to_partitioned(id) VALUES (1);
     INSERT INTO test.reference_to_partitioned(id, id_a, name_a) VALUES (2, 2, 'first');
   END IF;
-END$do$;
+END$do$;
+
+TRUNCATE TABLE test.products CASCADE;
+INSERT INTO test.products (id, name) VALUES (1,'product-1'), (2,'product-2'), (3,'product-3');
+
+TRUNCATE TABLE test.suppliers CASCADE;
+INSERT INTO test.suppliers (id, name) VALUES (1,'supplier-1'), (2,'supplier-2'), (3, 'supplier-3');
+
+TRUNCATE TABLE test.products_suppliers CASCADE;
+INSERT INTO test.products_suppliers (product_id, supplier_id) VALUES (1,1), (1,2), (2,1), (2,3);
+
+TRUNCATE TABLE test.trade_unions CASCADE;
+INSERT INTO test.trade_unions (id, name) VALUES (1,'union-1'), (2,'union-2'), (3, 'union-3'), (4, 'union-4');
+
+TRUNCATE TABLE test.suppliers_trade_unions CASCADE;
+INSERT INTO test.suppliers_trade_unions (supplier_id, trade_union_id) VALUES (1,1), (1,2), (2,3), (2,4);

test/fixtures/privileges.sql

@@ -151,6 +151,11 @@ GRANT ALL ON TABLE
     , schauspieler
     , filme
     , rollen
+    , products
+    , suppliers
+    , products_suppliers
+    , trade_unions
+    , suppliers_trade_unions
 TO postgrest_test_anonymous;
 
 GRANT INSERT ON TABLE insertonly TO postgrest_test_anonymous;

test/fixtures/schema.sql

@@ -2284,3 +2284,30 @@ $$ language sql;
 create or replace function test.overloaded_unnamed_param(x int, y int) returns int as $$
   select x + y;
 $$ language sql;
+
+create table products(
+  id int primary key
+, name text
+);
+
+create table suppliers(
+  id int primary key
+, name text
+);
+
+create table products_suppliers(
+  product_id int references products(id),
+  supplier_id int references suppliers(id),
+  primary key (product_id, supplier_id)
+);
+
+create table trade_unions(
+  id int primary key
+, name text
+);
+
+create table suppliers_trade_unions(
+  supplier_id int references suppliers(id),
+  trade_union_id int references trade_unions(id),
+  primary key (supplier_id, trade_union_id)
+);