dot-sits_labels_list: Sits labels processing function
In e-sensing/sits.data: Satellite Image Time Series Data Handling

Completes list.lst list as a named list (names are unique labels from data) according to a given function that receives each label as an argument.

1	.sits_labels_list(data, list.lst = list(), fun_label = function(lb) lb)

`data`	A sits tibble.
`list.lst`	Any named list whose names are unique labels from data input. Non-informed labels will be completed according to fun_label function.
`fun_label`	A function that will be executed for each label non listed in list.lst parameter. The result of is used as list.lst value for the respective label.