- `Category`,
- `FundingCategory`,
- `Language`,
- `MusicFocus`,
- `Topic`,
- `Type`

- `Category`,
- `FundingCategory`,
- `MusicFocus`

Feat: Generate visual data model

See merge request !23

refactor schedule REST API

Closes #101

See merge request !22

The conflict responses should be send with an HTTP 409 status code as
they’re defined in our documentation. This was not the case as the
dashboard couldn’t handle these error codes, but is now fixed in
dashboard@4a07ad9e.

Until now the steering API client was expected to submit two requests.

1. The initial schedule request, with a `schedule` object
2. A second schedule request, with an additional `solutions` object

This `solutions` object was empty, if no conflicts arose from the
submitted schedule in the first place. But instead of just creating the
requested schedule if no conflicts were detected we still required that
second round-trip, introducing possible race conditions in the client,
if another successful scheduling request was made between requests.

From now on the steering API will create schedules if no conflicts have
been detected and will only require the client to submit solutions if
there really are conflicts to solve.

The following attribute names were marked as deprecated in the schedule
request and have been replaced by their new names:

  dstart → first_date
  until → last_date
  tstart → start_time
  tend → end_time
  byweekday → by_weekday

Apart from that this commit fixes a few documentation errors.

django-cors-headers renamed the setting for the allowed origins and even
though it still supports the fallback the old setting as a fallback, we
want to be one the safe side.

When making the serialized fields explicit in
0ee3a655 we forgot to add the id field
that is used in various places.

- asgiref
- Django
- drf_spectacular
- Pillow
- pre-commit
- pycryptodomex
- pyparsing
- pytest
- python-magic
- pytz
- urllib3

Add API documentation

Closes #104

See merge request !21

If a collection is filtered by an invalid id (meaning the model the
query argument points to with that specific id does not exist), we no
longer return an error. Instead the filter is applied without a lookup.

Fixes #104

The CI should now automatically build an openapi.yaml file of the API
schema that is stored as an artifact.

This adds extensive API documentation based on the official API
documentation [1] and conflict resolution [2] documents.

Where possible field documentation was added to models or serializers,
so that other code like auto-generated forms can also profit from these
changes (hence the migration part of this commit).

The changes introduce two new API endpoints.

`/api/v1/schema/` exposes the API schema as an OpenAPI 3.0.3 document.
The standard format is yaml but can be switched to JSON by appending the
`?format=json` query parameter.

`/api/v1/schema/swagger-ui/` renders a visual representation of the
OpenAPI 3 specification with support for testing the individual API
endpoints including authentication.

[1]
https://gitlab.servus.at/aura/meta/-/blob/ec3c753d34ccb0269969808ac7dc28fff2ff1648/docs/development/api-definition.md
[2]
https://gitlab.servus.at/aura/meta/-/blob/ec3c753d34ccb0269969808ac7dc28fff2ff1648/docs/development/conflict-resolution.md

In addition to the

	?foo=1,2,3

filter syntax we now also support

	?foo=1&foo=2&foo=3
	?foo[]=1&foo[]=2&foo[]=3