#170 Fix tag filter OR, #171 fix async export

1. 6626e66e - #143 remove outdated export filter methods and tests
2. d969a3f6 - #170 fix: remove custom url encoding and rely completely on vue router
3. 9a818354 - #171 fix: make export asynchronous again
4. fc2a67e6 - #143 fix typo in export button tooltip
5. 10b82a9e - #174 fix: remove datasets from export which do not belong to user if user has role DATA_COLLECTOR
6. b73d1737 - #175 show total number of filtered datasets in frontend
7. 23a07938 - #172 fix pagination filter bug
8. 7a473b0f - #173 fix: disable default tag id functionality for dataset edit view
9. a05ad3a2 - frontend refactoring: fix delete dataset tag bug in tags form