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/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;