feat: add gendata command in bendsql

[sundy-li]

usage

gendata(tpch | tpcds, sf = <float>, override = 0 | 1); will generate tpch/tpcds tables in current database via duckdb extention

example:

root@localhost:18000/test> gendata(tpch, sf = 0.01, override = 1);

gendata(tpch, sf = 0.01, override = 1)

┌─────────────────────────────┐
│   table  │ status │   size  │
│  String  │ String │  UInt64 │
├──────────┼────────┼─────────┤
│ customer │ OK     │  130089 │
│ lineitem │ OK     │ 2551994 │
│ nation   │ OK     │    2195 │
│ orders   │ OK     │  598190 │
│ partsupp │ OK     │  437252 │
│ part     │ OK     │   77400 │
│ supplier │ OK     │   10653 │
│ region   │ OK     │    1018 │
└─────────────────────────────┘
root@localhost:18000/test> 

fixes #592

Note binary size increase from 34MB to 64MB now.