Add support for Json functions.

[chinamcafee]

There is a json array field in mysql table, which name is "permissions"，I can't use
Criteria.where("permissions").in(value)
to get results.

I also need dynamic SQL，so use
@Modifying @Query("UPDATE person SET firstname = :firstname where lastname = :lastname")
cannot satisfied my problem.

Is there any way to have both dynamic SQL ability and JSON_CONTAINS function support when I use spring-data-r2dbc?

[schauder]

Related: spring-projects/spring-data-relational#509