#143 advanced filtering, #129 previous/next button in dataset details and other bugfixes

1. 2b7155b4 - #143 backend implementation for advanced filtering
2. 7937ed87 - #129 add previous and next button in the detail view of a dataset
3. 1b5a05a5 - #143 frontend implementation for advanced filtering
4. c9399c5f - #143 remove dedicated 'Export' page and add export functionality in 'Datasets' page
5. b5bfc294 - #129 fix: query for previous / next dataset ignored sorting
6. 4eb44e7e - #129 #165 fix: previous / next buttons don't work if tag-filter is active
7. 7cbc73ce - #164 fix sorting bug for measurementDatetime and computedModified
8. c2a7c989 - #143 #167 fix browser history for dataset overview
9. ec996133 - #154 fix: cannot remove insectFamily from classification
10. f14061f8 - #163 fix: cannot update sensors operator or sensorLocation
11. 6634aaf0 - #157 update entity relationship diagram
12. fbde7b35 - #143 #166 fix browser history for dataset edit view
13. 1378da3b - #140 add directory name to error message for tags in data.json
14. 3a3fa105 - #129 reorder previous / next button in dataset edit view and jump after reload
15. 2ab3cc36 - #129 add previous and next button in the detail view of a dataset
16. 8014a203 - #143 improve layout and responsiveness of dataset filters panel