The gRPC protocol needs to support the JSON type

[nicecui]

What type of enhancement is this?

Tech debt reduction, User experience

What does the enhancement do?

The GreptimeDB already supports JSON type via SQL statements.
But gRPC protocol doesn't support it.
There are two things need to be done:

1. Support JSON type in the proto file.
2. Support JSON type in the Go SDK and Java SDK.

Implementation challenges

No response

[fengjiachun]

Java SDK done: GreptimeTeam/greptimedb-ingester-java#52

[fengjiachun]

@daviderli614 Let's add JSON Type support to the Go SDK.

[daviderli614]

@daviderli614 Let's add JSON Type support to the Go SDK.

Wait until I finish this PR：GreptimeTeam/greptimedb-ingester-go#51

[daviderli614]

Go SDK example: https://github.com/GreptimeTeam/greptimedb-ingester-go/blob/main/examples/jsondata/README.md

[nicecui]

done