[FEATURE]: BATCH API in node-postgres

### Feature hasn't been suggested before.

- [X] I have verified this feature I'm about to request hasn't been suggested before.

### Describe the enhancement you want to request

Reopening https://github.com/drizzle-team/drizzle-orm/issues/2291

Saw this was closed, but wondering why. Assume the following code:
```ts
await db.transaction(async (tx) => {
await tx.update(...);
await tx.update(...);
});
```

This will perform 2 updates inside a transaction. If one fails, the transaction fails. We can speed this up by putting each update inside a Promise.all, but we are still making 3 trips to our database:
1. start transaction
2. update rows
3. end transaction

It would be much more efficient to do something like
```ts
db.batch([
db.update(...),
db.update(...)
]);
```
Under the hood this could produce a single SQL statement that does the following:
```sql
BEGIN;
UPDATE table1 SET column_name1 = 'new_value' WHERE condition1;
UPDATE table2 SET column_name2 = 'new_value' WHERE condition2;
COMMIT;
```
Now I only have one chunk of SQL being sent to the database rather than 3.