* enhances rendering of tables
* enhances rendering of filter section
* reorganizes table filter codes into konova/filters/ folder and splits into mixins and table_filters
* refactors XYTableFilter classes to hold query_filter and checkbox_filter which are separate instances of django_filter.FilterSets
* improves render ability for frontend
* refactors table filters by introducing AbstractTableFilter, GeoReferencedTableFilterMixin, ShareableTableFilterMixin and RecordableTableFilterMixin
* adds full filter functionality
* refactors TableFilter inheritances for all objects