feat: Support round() function with two parameters

[ovr]

> select round(1234.56, -1);
+-----------------------------------+
| round(Float64(1234.56),Int64(-1)) |
+-----------------------------------+
| 1230                              |
+-----------------------------------+
1 row in set. Query took 0.002 seconds.
> select round(42.4382, 2);
+----------------------------------+
| round(Float64(42.4382),Int64(2)) |
+----------------------------------+
| 42.44                            |
+----------------------------------+
1 row in set. Query took 0.000 seconds.
> select round(42.4);
+----------------------+
| round(Float64(42.4)) |
+----------------------+
| 42                   |
+----------------------+
1 row in set. Query took 0.000 seconds.