Export reworked

...migrations/0005_alter_departmentcosts_options_and_more.py

app/vkk/migrations/0006_rename_time_receipt_create_time.py

...07_alter_departmentcosts_equivalents_per_hour_and_more.py

app/vkk/static/scripts/receipts.js

app/vkk/templates/vkk/customtags/form.html

...ours/accounting/projects/project/export/receipts/forms.py

...hours/accounting/projects/project/export/receipts/urls.py

...ours/accounting/projects/project/export/receipts/views.py

app/vkk/workhours/models.py