Support nested struct type

[navis]

{
  "name": "ci_profile",
  "typeName": "struct(
     base:boolean,
     life_style:string,
     segment:string,
     shopping_channel:string,
     family:struct(fmly_memb_cnt:int,hhld_memb_cnt:int,child_y:boolean,adult_child_y:boolean,married:boolean)
  )"
},