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/io-tests/configs/no-defaults-env.yaml

@@ -14,6 +14,7 @@ PGRST_DB_SCHEMAS: multi,   tenant,setup
 PGRST_DB_CONFIG: false
 PGRST_DB_TX_END: rollback-allow-override
 PGRST_DB_URI: tmp_db
+PGRST_DB_EMBED_DEFAULT_JOIN: inner
 PGRST_JWT_AUD: 'https://postgrest.org'
 PGRST_JWT_ROLE_CLAIM_KEY: '.user[0]."real-role"'
 PGRST_JWT_SECRET: c2VjdXJpdHl0aHJvdWdob2JzY3VyaXR5