sql: cleanup usage of ToSql

Moved custom ToSql trait including Send + Sync from lib.rs to sql.rs.
Replaced most params! and paramsv! macro usage with tuples.

Replaced paramsv! and params_iterv! with params_slice!,
because there is no need to construct a vector.

src/receive_imf/tests.rs

@@ -374,7 +374,7 @@ async fn test_no_message_id_header() {
         .sql
         .exists(
             "SELECT COUNT(*) FROM msgs WHERE chat_id=?;",
-            paramsv![DC_CHAT_ID_TRASH],
+            (DC_CHAT_ID_TRASH,),
         )
         .await
         .unwrap());