feat: support bitmap datatype

[sundy-li]

Display bitmap as a trivial string

SELECT
  build_bitmap([1,2,3,4,5,6]),
  113434343 :: Variant

┌───────────────────────────────────────────────────────┐
│ build_bitmap([1, 2, 3, 4, 5, 6]) │ 113434343::variant │
│              Bitmap              │       Variant      │
├──────────────────────────────────┼────────────────────┤
│ :0                               │ 113434343          │
└───────────────────────────────────────────────────────┘
1 row in 0.047 sec. Processed 1 rows, 1B (21.25 rows/s, 21B/s)

[everpcpc]

add an integration test?