Allow parameters in REBUILD statement

[Prometheorum]

It would be nice to be able to use parameters in REBUILD statements like so:

LET $table = "user";
LET $index = "name_idx";
REBUILD INDEX $index ON TABLE $table;

This would also allow setting these parameters with the .bind() method in the Rust SDK.

In current versions (1.5.4 and 2.0.9) this is unfortunately not possible and leads to a parsing error.