Added DELETE clause that takes a FROM clause

This makes T-SQL join deletes and MYSQL multi deletes possible.
```SQL
DELETE t1,t2 
FROM table1 AS t1 
INNER JOIN table2 t2 ...
INNER JOIN table3 t3 ...
```
`update` syntax can be used like this in standard HoneySQL, but `:delete-from` only accepts one table. A separate `delete` that takes a `from` clause mirrors `update`s existing flexibility in this.