Django-scientific-survey

Added support for Django 3.2.18.

- Added the possibility to specify and save template layouts for questions
- Layouts are possible to configure via YAML's `layouts` key. The examples of such configurations is given in `example_surveys/with_layouts`.
- If the template layouts are saved, they are saved for each user separately. By default they are private, but can be made public with the keys `public: true`.
- The saved template layouts can be re-used later, once they are saved. By default only the templates saved by each user separately or the ones marked as `public`.
- Changed JSON to YAML when importing surveys to enable multi-line layouts. YAML offers multiple advantages
- Multi-line strings, which is particularly handy for HTML template layouts
- More concise format, taking less space on disk

- Categories can now be treated as independent sub-surveys! This is useful if one wants to create a number of batches all of which are aimed at answering the same research question, but the experimental design requires each participant to see their own batch of questions. Additionally, one can control a number of responses per batch (1 by default). More specific important details are given below.
- Each category in the survey can be assigned a maximal number of responses to be collected
- Each such assignment is treated as an opportunity and becomes unavailable whenever a participant starts a survey, but not necessarily finishes it. The design decision was not to time out participants automatically to allow for variable completion time and the possibility of network failures. These booked opportunities are stored as instances of `CategoryBooking`.
- Decrementing `CategoryBooking` for a specific category-survey pair does open the opportunity for another participant to take the survey for this category. However, it also gives an opportunity to all participants who have already taken survey in this category to revise their answers without incrementing the respective `CategoryBooking`.
- Currently the categories are assigned to participants uniformly at random and there is no way to control it.

- Added the possibility to add ranges (sliders) as question types, distinguishing between integer ranges (range_int) and float ranges (range_float). It is possible to specify min, max and step for the range by re-using the already existing choices field