Add patient ordering by category

[Ashesh3]

Required for: coronasafe/care_fe#5197

This PR adds a new filter backend, PatientCustomOrderingFilter, to allow custom ordering of the Patient queryset based on the category_severity field. This field is annotated using a Case statement that maps each category value to its corresponding severity order. The filter backend accepts a new query parameter ordering to specify the ordering direction, which can be either ascending or descending.

This change also imports the Case and When classes from django.db.models to be used in the PatientCustomOrderingFilter`
implementation.

Overall, this PR enhances the functionality of the PatientViewSet by providing a new custom ordering option based on the severity of the patient's category.

@coronasafe/code-reviewers

[sonarcloud]

Kudos, SonarCloud Quality Gate passed!   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

No Coverage information
0.1% Duplication

[codecov-commenter]

Codecov Report

Patch coverage: 45.45% and project coverage change: -0.02 ⚠️

Comparison is base (5b13720) 56.22% compared to head (7fc67a1) 56.20%.

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Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1235      +/-   ##
==========================================
- Coverage   56.22%   56.20%   -0.02%     
==========================================
  Files         193      193              
  Lines        9491     9502      +11     
  Branches     1600     1604       +4     
==========================================
+ Hits         5336     5341       +5     
- Misses       4100     4106       +6     
  Partials       55       55              

Impacted Files	Coverage Δ
care/facility/api/viewsets/patient.py	45.56% <45.45%> (-0.01%)	⬇️

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[siddnikh]

LGTM

[vigneshhari]

If this is a requirement then i would recommend creating a migration and moving the values into something that is queryable. Do create an issue for that and track separately.

[vigneshhari]

Shouldn't you be ordering based on the new annotated field?

[Ashesh3]

@vigneshhari That is being already done, the annotated field is category_severity and here (.order_by(ordering)) ordering can be either category_severity or -category_severity.

[Ashesh3]

If this is a requirement then i would recommend creating a migration and moving the values into something that is queryable. Do create an issue for that and track separately.

For the separate issue, you mean a migration to move the values to numeric? So that we can return the category sorted in any order without needing a custom filter_backend? In that case I'd imagine the numeric value to be lowest [0] (Comfort) to highest [n] (Critical).