WIP: Resolve "Migrate to AlekSIS app"

Closes the following issues in TIC-Desk

• Closes #82
• Closes #88
• Closes #86 (closed)
• Closes #85
• Closes #90
• Closes #91
• Closes #19
• Closes #37

Depends on the following issues in AlekSIS

• AlekSIS/official/AlekSIS-Core#245 (closed) prio::1
• AlekSIS/official/AlekSIS-Core#331 (closed) prio::1
• AlekSIS/official/AlekSIS-Core#216 (closed) prio::1
• AlekSIS/official/AlekSIS-App-LDAP#10 (closed) prio::1
• AlekSIS/official/AlekSIS-Core#353 (closed) prio::1
• AlekSIS/official/AlekSIS-Core#354 (closed) prio::1
• AlekSIS/onboarding/AlekSIS-App-Postbuero#1 (closed) prio::1 wip
• AlekSIS/official/AlekSIS-Core#239 (closed) prio::2
• AlekSIS/official/AlekSIS-Core#240 (closed) prio::2
• AlekSIS/official/AlekSIS-App-Alsijil#69 (closed) prio::2
• AlekSIS/official/AlekSIS-Core#180 prio::2
• AlekSIS/official/AlekSIS-Core#311 (closed) prio::2
• AlekSIS/official/AlekSIS-Core#219 prio::3
• AlekSIS/official/AlekSIS-Core#215 prio::3
• AlekSIS/official/AlekSIS-Core#212 (closed) prio::3
• AlekSIS/onboarding/AlekSIS-App-Postbuero#4 prio::3
• AlekSIS/official/AlekSIS-Core#122 (closed) prio::3
• AlekSIS/official/AlekSIS-Core#259 prio::3

TODO

• Discuss and implement account registration
• Make event registration work again
• Add Registration model for event registrations
• Use reversion everywhere
• Create Activity when…
  • Event was created
  • Voucher was created
  • User registered for an event
• Move stuff to other Apps:
  • PGPKey to AlekSIS-App-Postbuero
  • SSHKey to AlekSIS-App-LDAP
  • MailAddress to AlekSIS-App-Postbuero
• is_member should not need the member group
• Rename TeckidsProject to TeckidsEvent (and variable project to event)
• CHANNEL_CHOICES should be configurable in frontend
• Use email code from AlekSIS' core
• Use reversion decorator in EventRegistration views
• Add edit form for registrations so that users can edit their registrations
• Use IBANField
• used_person_uid on Voucher should be ForeignKey on Person
• Use timezone.now() and timezone.today() instead of datetime.{now,today}().
• guardian.get_or_create: Match only on email
• If guardian exists, update fields
• Use AdditionalField from core instead of RegistrationField
• Rebuild TeckidsEvent model with relation on Group
• Write own forms for user registration
• Implement management of guardians
• Update translations

Verify functionality

• General
  • Translations
  • Permissions
  • PaperCSS templates
  • Member management
  • PaperCSS templates
  • Activities
  • Performance tests
• Events
  • Event feedback
  • Event registration
  • Additional fields
  • Voucher management
  • Registration management
• Account
  • Account registration
  • Mail address registration
  • PGP and SSH key management
  • Change password

Release

• Reformat (make lint clean)
• Re-create migrations
• Release 2.0b0
• Test with at least one event
• Release 2.0

Migrate from ticdesk to ticdesk2

• Sync existing mail addresses from LDAP to MailAddress objects
• Sync existing PGP keys from LDAP to PGPKey objects
• Sync existing SSH keys from LDAP to SSHKey objects
• Move existing events to TeckisProject objects