add support for postgres ssl mode and root cert

llama_stack/providers/utils/kvstore/config.py

@@ -75,6 +75,8 @@ class PostgresKVStoreConfig(CommonConfig):
     db: str = "llamastack"
     user: str
     password: str | None = None
+    ssl_mode: str | None = None
+    ssl_root_cert: str | None = None
     table_name: str = "llamastack_kvstore"
 
     @classmethod

llama_stack/providers/utils/kvstore/postgres/postgres.py

@@ -30,6 +30,8 @@ class PostgresKVStoreImpl(KVStore):
                 database=self.config.db,
                 user=self.config.user,
                 password=self.config.password,
+                sslmode=self.config.ssl_mode,
+                sslrootcert=self.config.ssl_root_cert,
             )
             self.conn.autocommit = True
             self.cursor = self.conn.cursor(cursor_factory=DictCursor)