fix: :bug: Change way of dataframe export (#640)
* fix: :bug: Change way of dataframe export
Change the way of dataframe export for correlation export.
Fixes #639
* fix: :white_check_mark: Update test for correlation
* feat: :recycle: Update constant definitions
* feat: :pushpin: Redifne of fwhm voigt
Redfined full maximum half width for `fwhm_g` and `fwhm_l` are equal
* fix: :test_tube: Fixed broken comparsion
