Fix template not being able to access PaymentVariant name

Closes #35

See merge request !86

Resolve "Payment variant migration creates invalid polymorphic models"

Closes #34

See merge request !85

Fix missing class var adaption

Closes #32

See merge request !81

Resolve "Adapt to new core address model"

Closes #31

See merge request !80

Resolve "Adjust to RegistryObject classvar name change"

Closes #32

See merge request !79

Payment variants

See merge request !25

Update tox.ini

See merge request !62

Update pyproject.toml

See merge request !63

Update dependency django-payments to v3

See merge request !61

Update .gitignore

See merge request !71

Update .prettierignore

See merge request !54

Update .dev-js/.eslintrc.js

See merge request !72

Update .dev-js/package.json

See merge request !64

Delete .eslintrc.js

See merge request !73

Translations update from Weblate

See merge request !60

Resolve "Add graphql type for paymant choices"

Closes #29

See merge request !74