Change way to handle JSON outputs

[statnmap]

Why?

• Nested lists are difficult to handle automatically

Linked to #51 What?

• A proposition to only handle the first level, the user will have to handle himself sub-lists.

• This will be a breaking change when implemented !

• [ ] Need to verify that main object is indeed a list, named list, in case, we want to retrieve a sub-element

workitem_tbl <- multilist_to_tibble(workitem)
wifields <- multilist_to_tibble(workitem_tbl$fields[[1]]) # << 
names(wifields)
wifields$System.State

# Otherwise
> wifields <- multilist_to_tibble(workitem_tbl$fields)
Error in `vec_cbind()`:
! Names can't be empty.
✖ Empty name found at location 1.
Run `rlang::last_error()` to see where the error occurred.