This commit is a rough port to Django 2.1, Python 3 and a Docker based local
development setup. Tests fail/error but migrations and the web frontend are
already runnable. Task queue functionality is untested and translations seem to
have trouble.
- fix unique constraints on CustomerDiskSpaceOption and
CustomerUserDatabaseOption to allow multiple options from the same template
for hosting packages
- fix disk space calculation in CustomerHostingPackage
- implement hostingpackages forms AddDiskspaceOptionForm, AddMailboxOptionForm,
AddUserDatabaseOptionForm
- implement hostingpackages.views.AddHostingOption
- add new URL pattern add_hosting_option to hostingpackages.urls
- add template hostingpackages/add_hosting_option.html
- link items on hostingpackages/customerhostingpackage_option_choices.html to
add_hosting_option
- rename CreateHostingPackage to CreateCustomerHostingPackage
- add new CreateHostingPackage that allows to select a customer
- rename CreateHostingPackageForm to CreateCustomerHostingPackageForm
- add new CreateHostingPackageForm that has a customer field
- add new URL pattern create_hosting_package, rename existing pattern to
create_customer_hosting_package
- modify template dashboard/user_dashboard to use the correct URL name
