Bug fixes

Biggest update in years as we are leaving sass behind to use post css

Fix special characters in export names

Fix resetting of the hierarchy setting from the overview of terms within a vocabulary

Fixed some coding standards and saving of relation in edit form for single parent hierarchy terms

Fixed popup IDs duplication in lists of content described in #2932979: Multi popup issue.
Fixed JavaScript coding standards warnings.

This release fixes compatibility with older releases of PHP.

Changes since 7.x-1.19: