[Tracking issue] Add json datatype

[CookiePieWw]

What type of enhancement is this?

Other

What does the enhancement do?

Support to store and query json data as an independent datatype.

Tasks

• [x] Build a benchmark to choose the representation of json inside memory and SST files.
  • see https://github.com/CookiePieWw/json-format-in-parquet-benchmark for more information.
• [ ] RFC https://github.com/GreptimeTeam/greptimedb/pull/4515
• [ ] Add json datatype and other related support.
  • https://github.com/GreptimeTeam/greptimedb/pull/4619
  • Currently the insertions of json type through "PREPARE" and "EXECUTE" stmt are not available.
• [ ] Add UDFs for querying json.
  • [x] Add casts between jsonb value and other types, e.g. parse_jsonb("{\"a\": \"b\"}")
    • [x] string to json: see to_json in #4619
  • [x] Add functions to query inside json through paths, e.g. get_by_path_int(".a.b", json) https://github.com/GreptimeTeam/greptimedb/pull/4720
  • [x] Add functions to check if the given json is of specified json type. https://github.com/GreptimeTeam/greptimedb/pull/4726