Virtualized table - fixes after code review

[MikaelNordberg]

During code review we found out that we shall try to fix the following things to make the code easier to maintain:

• Place table files in subfolders for desktop, mobile, utils and so on. - DONE
• Try to separate the scss file into different scss files for desktop, mobile and table. - DONE
• Create stories for desktop and mobile. -DONE
• Maybe create a LegacyTable component.
• Move functionality in Table to utility functions.
• Some changes in code. - DONE

[AsaArrhen]

From Jira
https://statistics-norway.atlassian.net/browse/PXWEB2-1069
https://statistics-norway.atlassian.net/browse/PXWEB2-1071
https://statistics-norway.atlassian.net/browse/PXWEB2-1070 )