[C++] Add a VisitIntegerType helper

### Describe the enhancement requested

In `visit_type_inline.h` we have a `VisitType` that dispatches all existing data types to a generic callable (presumably a lambda or template function).

It would be useful to have a similar `VisitIntegerType` helper that assumes its input is an integer type. This would help implementing helpers for dictionary indices, take indices, etc.

For example this snippet could be reimplemented more tersely using said helper:
https://github.com/apache/arrow/blob/154962c364bc210c10ef16680f54a115b624b400/cpp/src/arrow/util/dict_util.cc#L61-L79

### Component(s)

C++