Navigate a period ('.') delimited path of attribute values into the
oil data structure and set a value at that location in the
structure.
Example paths:
- sub_samples.0.metadata.sample_id (sub_samples is assumed to be
- a list, and we go to the zero index for that part)
THIS
- physical_properties.densities.-1 (densities is assumed to be a
list, goes to the last item)
- physical_properties.densities.+ (appends an item to the
densities list and goes to that part. the index value
is assumed to be -1 in this case)