fix csv input

Description

The reading of csv files for user defined states was broken (and never tested).

This MR will

• fix the low level routines (convert to iso_c_bindings)
• add low level tests in the components section
• add a physical test, also testing the correct remapping to the grid
• allow reading of real states for TD runs, which require complex wave functions
• update and fix the documentation
• add test for obf files
• add test for ncdf files

News snippet

Fix the import of user defined states from csv files.

Checklist

• I have checked that my code follows the Octopus coding standards
• I have added tests for all the new features added in this request.